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What type and amount of exercise (if any) should I do if I'm stressed - science has the answer: Wisdom Wednesdays · Hardiness with Dr Paul Taylor

• 0:06
  Speaker 1: Everybody, Welcome to another edition of Wisdom and Wednesdays. Today
• 0:09
  Speaker 1: we're going to talk about exercise and cortisol, and more specifically,
• 0:13
  Speaker 1: we're going to talk about how much exercise appears to
• 0:16
  Speaker 1: be optimal for lowering cortisol than people who are stressed.
• 0:20
  Speaker 1: And also I'm going to discuss why a temporary rising
• 0:23
  Speaker 1: cortisol after a hard workout is not necessarily something to fear.
• 0:29
  Speaker 1: Cortisol has developed a really bad reputation. It's become one
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  Speaker 1: of those hormones that people talk about as if the
• 0:36
  Speaker 1: goal is to eliminate it completely. And you will see
• 0:40
  Speaker 1: all sorts of claims online that your workout is spiking
• 0:44
  Speaker 1: your cortisol, your morning coffee is spiking your cortisol, your
• 0:48
  Speaker 1: morning routine is spiking your cortisol, and apparently any activity
• 0:52
  Speaker 1: that requires effort is destroying your hormones. But cortisol is
• 0:57
  Speaker 1: not the enemy. Without it, you would be dead. Cordisol
• 1:01
  Speaker 1: is an essential hormone. You need it to wake up
• 1:03
  Speaker 1: in the morning, to mobilize energy, to maintain your blood pressure,
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  Speaker 1: and respond to challenges and adapt to the stress of exercise.
• 1:12
  Speaker 1: So the issues not whether cordisol ever rises. The issue
• 1:17
  Speaker 1: is whether your cordisol system is functioning appropriately, whether it
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  Speaker 1: rises when you need it, comes down when the stressor
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  Speaker 1: is over, and maintains a healthy daily rhythm. And we
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  Speaker 1: know that it should spike or peak first thing in
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  Speaker 1: the morning, just after you wake up or I've done
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  Speaker 1: around thirty minutes, and then it should drop off into
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  Speaker 1: the evening. Now to get back to the topic where
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  Speaker 1: there's a couple of research papers that really help us
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  Speaker 1: to understand this very very well. The first study looked
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  Speaker 1: at exercise dose and chronic cordisol reduction. Right, So the
• 1:56
  Speaker 1: paper is called the Optimal Exercise Modality and Dose for
• 2:00
  Speaker 1: Cortisol Reduction in Psychological Distress, a Systematic Review and Network
• 2:05
  Speaker 1: meta Analysis, and it was published just last year in
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  Speaker 1: the journal Sports. And that the researchers included forty four
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  Speaker 1: randomized control trials involving I've touched over three thousand participants
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  Speaker 1: who were all experiencing psychological distress, and that included people
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  Speaker 1: with elevated symptoms of stress or anxiety or depression. Now, importantly,
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  Speaker 1: this was not a study of what happens to cortisol
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  Speaker 1: in the five minutes after a workout. The interventions had
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  Speaker 1: to last for at least three weeks, and the average
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  Speaker 1: intervention lasted approximately twelve weeks, with the participants generally exercising
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  Speaker 1: three times per week for about fifty five minutes per session,
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  Speaker 1: so just under an R. And what the researchers were
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  Speaker 1: looking at primarily was the longer term change in baseline
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  Speaker 1: cordisole before the exercise program to after it. Now, where
• 3:02
  Speaker 1: multiple cortisol measurements were available, they prioritized mourning cortisol because
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  Speaker 1: that is kind of the key metric here. So the
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  Speaker 1: findings are mainly about improving chronic a resting cortisol regulation, right,
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  Speaker 1: not the immediate hormonal response to one exercise session, which
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  Speaker 1: I'll talk about later, but it's that baseline waking cortiso.
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  Speaker 1: When you are have got hyper cortisoladia that long term
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  Speaker 1: your diurnal rhythm tends to actually be affected. Initially it
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  Speaker 1: tais spikes, but then with real bad stuff, the rhythm
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  Speaker 1: tends to flip. But what this find and this was
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  Speaker 1: just looking at that baseline of people who were stressed,
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  Speaker 1: So these aren't people who were severely burnt out. They're
• 3:53
  Speaker 1: the people whose rhythm flips. But the overall finding here
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  Speaker 1: was that exercise produced a moderate reduction in waking corsol,
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  Speaker 1: which is actually a good thing, but not all exercise
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  Speaker 1: was equal, and yoga you will probably not be surprised
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  Speaker 1: that produced the largest and most reliable reduction. Chigung ranked second,
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  Speaker 1: followed by a multi component exercise that was continuous aerobic
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  Speaker 1: exercise and then high intensity interval training, which actually as
• 4:23
  Speaker 1: well did reduce it. And the researchers also examined the
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  Speaker 1: dose or the amount, using something called met minutes per week,
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  Speaker 1: so and met is basically the amount of energy that
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  Speaker 1: you burn at rest. So basically one met is roughly
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  Speaker 1: the amount of energy that you will use by sitting quietly.
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  Speaker 1: So if an activity is rated at five mets and
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  Speaker 1: you do it for thirty minutes, that's one hundred and
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  Speaker 1: fifty met minutes. So what that means is something that's
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  Speaker 1: five minutes raises your basal basical energy use by five
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  Speaker 1: times over six and we see that quite a lot
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  Speaker 1: with exercise. It goes up to ten fifteen mets, so
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  Speaker 1: that one hundred and fifty met minutes would be exercise
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  Speaker 1: at five minutes, which is kind of moderate for about
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  Speaker 1: thirteen minutes, right, So that's just to give you a
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  Speaker 1: baseline what the study find was is there was a
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  Speaker 1: nonlinear response between exercise dose and corzo resuction. In all
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  Speaker 1: the words, more was not always better, and they found
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  Speaker 1: that the optimal overall dose was approximately five hundred and
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  Speaker 1: thirty met minutes per week and the minimum dose associated
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  Speaker 1: with the clinically meaningful effect was around three hundred met
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  Speaker 1: minutes per week. So in practical terms, what does that
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  Speaker 1: translate to ninety to one hundred and eighty minutes of
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  Speaker 1: low intensity exercise per week. Kind of gives you that
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  Speaker 1: three hundred to five hundred and thirty or sixty t
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  Speaker 1: one hundred and twenty minutes of moderate or approximately forty
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  Speaker 1: five to ninety minutes, so you can still do vigorous
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  Speaker 1: exercise and get meaningful reductions in your baseline cortisol. So
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  Speaker 1: the precise numbers they depended on the intensity, but the
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  Speaker 1: broad message is pretty clear that for stressed individuals, a
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  Speaker 1: moderate and sustainable exercise dose may be better for corso
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  Speaker 1: regulation than simply doing as much hard training as you
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  Speaker 1: possibly can. Right, and the study suggested that that sessions
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  Speaker 1: lasting thirty to sixty minutes performed more than three times
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  Speaker 1: per week produced particularly strong results. Right and longer interventions
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  Speaker 1: were also associated with larger cordisol reduction. So the longer
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  Speaker 1: you continue to exercise, the better the effect was. And
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  Speaker 1: then for every additional week of exercise intervention, the corzo
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  Speaker 1: lowering effect improved slightly. Right, So that tells us something
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  Speaker 1: important that the biggest benefits come from consistency rather than
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  Speaker 1: just going out and exercising a hate one week and
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  Speaker 1: not doing anything the next week. And so regular movement
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  Speaker 1: repeated week after week is what appears to help recalibate
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  Speaker 1: the stress response system. And it really aligns with the
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  Speaker 1: government guidelines of one hundred and fifty to three hundred
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  Speaker 1: minutes of moderate or seventy five to one hundred and
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  Speaker 1: fifty minutes of vigorous but spread over at least five sessions.
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  Speaker 1: It's actually doing it consistently. That's key. So why did
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  Speaker 1: yoga perform so well. It had the strongest cordiso lowering
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  Speaker 1: effect and actually had the highest level of evidence as well. Now,
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  Speaker 1: it doesn't necessarily mean that yoga's superior to all other
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  Speaker 1: forms of exercise for every health outcome. Yoga is not
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  Speaker 1: going to increase your VO two max. It's not going
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  Speaker 1: to build much muscles, certainly not to the same extent
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  Speaker 1: of running and resistance training, but for reducing levels of
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  Speaker 1: physiological or rosal, which is known as stress. It has
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  Speaker 1: some obvious advantages. It combines movement control, breathing, focused attention,
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  Speaker 1: and in many cases mindfulness. And it may be this
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  Speaker 1: combination of increased parasympathetic activity the rest digests recover side
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  Speaker 1: of the nervous system while also improving negative feedback within
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  Speaker 1: the HPI access and that's the system connecting the brain,
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  Speaker 1: the prajuritary gland and the adrenal glands that regulates cortisol.
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  Speaker 1: So yoga it's not simply stretching. It combines several stress
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  Speaker 1: regulation mechanisms in a single activity right where you're actually moving.
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  Speaker 1: But there is also that breath work, that mindfulness and
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  Speaker 1: she gong may work through similar pathways. So the message
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  Speaker 1: it's not that everybody has to abandon running and take
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  Speaker 1: up yoga. It's that when the primary goal is to
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  Speaker 1: lower chronic stress and improve cortisol regulation, and lots of
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  Speaker 1: different exercises helped, but you should probably incorporate yogurt chi
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  Speaker 1: gung into your exercise routine. So what about hit. Now,
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  Speaker 1: this is where things become interesting. So in that paper
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  Speaker 1: the HIT it did have an effect on chronic cortisol,
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  Speaker 1: but not particularly well. It wasn't as good as I
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  Speaker 1: said as yogurt chigung or some other things, and and
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  Speaker 1: some some of the studies with a NAT suggested that
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  Speaker 1: HIT could potentially increase cortisol in people who were psychological
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  Speaker 1: psychologically stressed. But that finally could be easily misinterpreted. You
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  Speaker 1: could read the headline and go hit uses cordsol. Therefore
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  Speaker 1: head is bad for you, and I see that a
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  Speaker 1: lot nigh with both perimenopaus and postmenopausal women. You shouldn't
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  Speaker 1: do HIT because it increases your cortisol. But that confuses
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  Speaker 1: an acute response with a chronic problem. And there's a
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  Speaker 1: second paper that helps to clarify this. So the second
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  Speaker 1: paper is called a Cute Effect of HIT on Testosterone
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  Speaker 1: and cortisol levels in healthy individuals. The systematic review in
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  Speaker 1: meta analysis, and it was published in the Scandinavian Journal
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  Speaker 1: of Medicine and Sports Science in twenty twenty one. They
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  Speaker 1: looked at fifty three studies. Unlike the first paper, this
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  Speaker 1: study examined the response to a single session of HIT,
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  Speaker 1: and it measured cortisol immediately after exercise, then at thirty minutes,
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  Speaker 1: sixty minutes, two hours, and three hours, and twenty four hours,
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  Speaker 1: and the pattern was really interesting. So immediately after the
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  Speaker 1: hit session, cordisol increased significantly, and that's no surprise to
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  Speaker 1: any sports scientists, right because cordisol is used to mobilize
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  Speaker 1: energy when you're exercising, and particularly when you're exercising either
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  Speaker 1: for a long time or at higher intensity. So if
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  Speaker 1: you just stop right there, what you would say is
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  Speaker 1: high intensity exercise is bad forew because it increases your
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  Speaker 1: levels of cortisol. But what they find was that after
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  Speaker 1: sixty minutes it real me and delevate in some of
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  Speaker 1: the studies, but the rise was smaller and less consistent
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  Speaker 1: in others. And then something interesting happened. After two hours
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  Speaker 1: of hit corzol was approximately twenty three percent below the
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  Speaker 1: pre exercise baseline. After three hours it was thirty six
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  Speaker 1: percent but below that baseline, and by twenty four hours
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  Speaker 1: it had returned to baseline. So the overall pattern is
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  Speaker 1: this a large initial rise, then a period of elevation
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  Speaker 1: lasting for about an hour, then a drop below baseline
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  Speaker 1: at two to three hours, and then a gradual return
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  Speaker 1: to normal by the following day. Now that is not
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  Speaker 1: evidence of a broken stress system, and then that is
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  Speaker 1: not saying that you're adding stress into the system. This
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  Speaker 1: is evidence of a responsive stress system. So exercise is
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  Speaker 1: a stressor. That is partly why it works. And when
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  Speaker 1: you perform hit, your body must mobilize glucose, increase cardiovascar output,
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  Speaker 1: redirect blood flow, and maintain performed. It's under intense metabolic demand,
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  Speaker 1: and cordizole makes that happen. I mean what also happens
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  Speaker 1: when you're exercising is your blood pressure goes up and
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  Speaker 1: then afterwards it drops below baseline. So this is a
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  Speaker 1: normal response to an acute stressor where we then actually
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  Speaker 1: bounds back the other way, and it is a part
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  Speaker 1: of the body's normal response to challenge. So we need
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  Speaker 1: to stop treating every temporary increase in a stress hormone
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  Speaker 1: is pathological. As I said, your blood pressure rise, your
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  Speaker 1: heart rate rise, your body temperature rise, your breathing rate rises,
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  Speaker 1: so does your corso and particularly if it's high intensity
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  Speaker 1: or it goes for a long period of time. And
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  Speaker 1: a healthy stress response system looks like this activation when required,
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  Speaker 1: adaptation to the challenge, and then recovery afterwards, and the
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  Speaker 1: HIT paper showed exactly that pattern. Cordisole increased when the
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  Speaker 1: body needed additional energy and then failed below baseline during
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  Speaker 1: the recovery period, and by twenty four hours, as I said,
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  Speaker 1: it was back to normal. This is a great example
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  Speaker 1: of hornmesis, which you've heard me bang on about so
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  Speaker 1: many times, the process through which a manageable dose of
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  Speaker 1: stress stimulates adaptation, challenge the system, you're allowed to recover,
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  Speaker 1: and the system becomes more capable. So the problem's not
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  Speaker 1: stress itself, it's ex excessive stress without sufficient recovery. So
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  Speaker 1: let's say and kind of bring these two things together,
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  Speaker 1: and who should be cautious with HIT? So it's pretty
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  Speaker 1: clear that healthy people should not be frightened by an
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  Speaker 1: acute course, only increase after hit. But that doesn't mean
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  Speaker 1: that everybody should be doing maximum high intensity training every
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  Speaker 1: single day. Those two papers I talked about involved different
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  Speaker 1: populations and they answered different questions. The HIT paper was
• 13:54
  Speaker 1: primarily on healthy, relatively young individuals, the average participants about
• 14:00
  Speaker 1: twenty four and they were trained record is the active
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  Speaker 1: or competitive and the exercise. Those paper examine people who
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  Speaker 1: were experiencing psychological distress. Now they're not interchangeable groups. So
• 14:13
  Speaker 1: somebody's who's eating reasonably well and sleeping well, but just
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  Speaker 1: going through the normal stresses of life. It's pretty clear
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  Speaker 1: that doing exercise, and particularly a bit of vigorous exercise
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  Speaker 1: can actually be a good thing, and can particularly after
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  Speaker 1: a stressful day, and you go and you do a
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  Speaker 1: bit of hip training, you can then an or two
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  Speaker 1: leader you drop down below baseline, So it's actually a
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  Speaker 1: good thing. So in that context, you know, bringing HIT
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  Speaker 1: into your routine is a good thing. But someone who
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  Speaker 1: is chronically stressed, is sleep deprived, they're underfueling, they're emostly exhaustion.
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  Speaker 1: They may respond differently. So in that context, more high
• 14:59
  Speaker 1: intense the exercise may simply add another demand onto a
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  Speaker 1: ready overloaded system. So exercise prescription should match the person,
• 15:10
  Speaker 1: not just the physiology textbook. For a highly stressed individual,
• 15:14
  Speaker 1: the first prior priority might be walking, moderate cycling, yoga,
• 15:20
  Speaker 1: chigung a bit of resistance training, and some other forms
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  Speaker 1: of movement that make you feel better rather than make
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  Speaker 1: you feel completely wiped out. Now, HIT can still have
• 15:30
  Speaker 1: a place, but I wouldn't be doing CrossFit five or
• 15:33
  Speaker 1: six times a week. Maybe you do the hit once
• 15:36
  Speaker 1: or twice a week, and then the other three or
• 15:38
  Speaker 1: four times a week. It's the more that moderate the
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  Speaker 1: yoga that you're gong and a bit of low intensity cardio.
• 15:44
  Speaker 1: Then we have the question that it seems to be
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  Speaker 1: coming up a lot, and whether there are differences between
• 15:51
  Speaker 1: men and women. And there are certain people out there,
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  Speaker 1: particularly doctor Stacey Sims, who's awesome, it's been on my podcast,
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  Speaker 1: who is very anti hit for for women, particularly perimenipuzzal
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  Speaker 1: and postmenopausal women. And whilst she's one hundred percent right
• 16:10
  Speaker 1: in saying that women are not small men and that
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  Speaker 1: they are underrepresented in the research, I don't think we
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  Speaker 1: can make those big statements that certain women should not
• 16:23
  Speaker 1: do this now. Interestingly, to the point of underrepresentation in
• 16:28
  Speaker 1: the HIT analysis, it was overwhelming mele only women only
• 16:32
  Speaker 1: represented about nine percent of the total sample, and many
• 16:37
  Speaker 1: of the analysis that did the thirty sixty one hundred
• 16:40
  Speaker 1: and twenty one hundred eighty minutes contain no women at all,
• 16:44
  Speaker 1: and the researchers they couldn't meaningfully determine whether the court
• 16:48
  Speaker 1: is all response differed between men and women, right, so
• 16:51
  Speaker 1: we cannot confidently say that the exact same rise and
• 16:54
  Speaker 1: fall pattern happens the same magnitude in both sexes. But
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  Speaker 1: this research and other research that I've looked at, doesn't
• 17:02
  Speaker 1: say the opposite. It doesn't say that women suffer or
• 17:06
  Speaker 1: or have a completely different response to men. I think
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  Speaker 1: that is a step too far from the research that
• 17:13
  Speaker 1: I've read. And if anybody has some research showing that
• 17:17
  Speaker 1: there are differences between men and women, I love to
• 17:20
  Speaker 1: see them. Maybe theoretically from that point of view, if
• 17:24
  Speaker 1: you are in a stress stage of life, whether that's
• 17:27
  Speaker 1: perrier of postmenopause or that's just your stressed individual, probably
• 17:33
  Speaker 1: I think the best advice is to follow the research
• 17:36
  Speaker 1: from the first paper, where you might do one hit
• 17:40
  Speaker 1: session a week, but then your other stuff is more
• 17:43
  Speaker 1: the yoga, the gigong, the lower intensity stuff, but making
• 17:47
  Speaker 1: sure that you're doing some strength training as well. That
• 17:49
  Speaker 1: would be my takeout from this, and the broader takeout
• 17:54
  Speaker 1: for everybody who's experiencing high psychological stress is to really
• 18:00
  Speaker 1: go for that sustainable weekly target of around the three
• 18:04
  Speaker 1: hundred to five hundred and thirty met minutes. This has
• 18:07
  Speaker 1: been clinically proven to reduce your baseline cortisol. And again,
• 18:13
  Speaker 1: what does that mean? It could mean something like this, right,
• 18:16
  Speaker 1: three thirty minute brisk walks, add in a couple of
• 18:20
  Speaker 1: thirty minute strength training sessions and two yoga sessions or
• 18:25
  Speaker 1: chigung sessions, something like that. And if you do enjoy
• 18:29
  Speaker 1: some of the higher intensity interval training, I think it's
• 18:32
  Speaker 1: okay to do one or two sessions, but it's just
• 18:35
  Speaker 1: not doing it all the time, and making sure that
• 18:37
  Speaker 1: you're doing some of that slower rhythmic stuff that has
• 18:41
  Speaker 1: breath lead nobility, or simply walking out doors in nature.
• 18:47
  Speaker 1: So hopefully that gives you a little bit of clarity
• 18:49
  Speaker 1: of what is a particularly complex but important subject because
• 18:58
  Speaker 1: lots of us are stressed and it is really clear
• 19:01
  Speaker 1: that avoiding exercise is not the answer. That's it for
• 19:06
  Speaker 1: this week, folks, Catch you next time.