Weekly Q&A: Nasal breathing during exercise, CBD for sleep and recovery, optimizing exercise Rx for fitness and longevity, and more!
Welcome to your resource for optimizing mental and physical performance.
Each week, I’ll answer some questions from audience members (like you!)
This week, I’ll answer questions on:
Nasal vs. mouth breathing for exercise performance
CBD for sleep and recovery
Energy expenditure during exercise
Optimizing exercise prescription for fitness and longevity
Do you have questions about a particular supplement, recovery strategy, or training technique?
Please take a minute to check out some sponsors and affiliates whom I love.
Examine.com: For optimizing decisions about your nutrition and supplements. Examine is the largest database of nutrition and supplement information on the internet.
Basis Health: For optimizing your daily energy schedule. Basis turns your health data into actionable recommendations.
Veri: For optimizing your blood glucose. Veri combines a continuous glucose monitor (CGM) with an easy-to-use app to help you find the right foods and habits for your body. Get a 20% discount on your purchase when you use the code BRADY20 at checkout.
PodScholars: For digestible summaries of scientific research. PodScholars is the first podcasting platform and database specifically geared towards published research, where scholars, researchers, and other experts can broadcast published science as audio or video casts.
Could there be any benefit to doing low- or moderate-intensity exercise sessions with nose breathing only?
There’s a lot of talk on nose/nasal breathing lately, and I think the “hype” is somewhat justified due to the well-known physiological effects that deep nasal breathing can have: regulating heart rate and blood pressure, decreasing sympathetic nervous system activity, and promoting relaxation.
From a performance perspective, I’m not quite sure that you’ll get an actual improvement in oxygenation or efficiency using nasal breathing, and from the studies I’ve read, there doesn’t seem to be a difference in many parameters during exercise using nose or mouth breathing. In fact, at higher exercise intensities, there may be a limitation to nose breathing, as it will limit how much air you’re able to inspire, and there might be a slight elevation in heart rate. At such a high breathing/air flow rate, nose breathing will probably be more stressful and provide more resistance than mouth breathing will.
I do think that nose breathing can be useful at lower exercise intensities as a way to “force” you to slow down on an easy or recovery day. By that, I mean that if you limit yourself to an intensity where nose breathing is comfortable, it can be a good way not to push too hard. Focusing on nose breathing can also be a good way to enter a “meditative” or flow state during exercise.
Ultimately, breathe in a way that you find comfortable, and one that reduces your perceived exertion the most.
Do you have any thoughts on CBD and sleep performance? Sleep is a proven recovery tool, so it seems like CBD could have the potential for improving performance by enhancing sleep quality.
There’s not a lot of research on CBD (cannabidiol) for any condition, including sleep. This hasn’t stopped companies from selling and marketing CBD for everything from chronic pain to insomnia to athletic performance. There’s a lot of anecdotal evidence from CBD users about the benefits, but unfortunately, not a lot of the claims are supported by rigorous evidence.
But, given CBD’s calming effects on the nervous system, there may be some biological plausibility for this compound to improve sleep. Individuals with good sleep might not see a benefit, but since CBD has anxiety- and pain-reducing effects, it may help improve sleep for people with these conditions. Anxiety and pain can often lead to insomnia, so any product that reduces either symptom may help improve sleep by proxy.
As far as athletic performance and recovery are concerned, as I mentioned above, there’s little evidence to support the benefits of CBD. At most, it may help to promote a sense of calm and relaxation, which could certainly help to wind down after a workout or a competition. I’m curious to see what CBD research will show us in the coming years. For now, I think the placebo effect explains a lot of the perceived benefits.
Does a 250 lb person who runs a 12-minute mile and a 150 lb person who runs a 12-minute mile have the same MET (metabolic equivalent) value for that exercise? In this case, would heart rate be better to use to gauge intensity considering these people have different BMIs?
For those unfamiliar, a MET refers to a metabolic equivalent of exercise — it’s a value given to different activities that compare their energy expenditure to average energy expenditure at rest.
1 MET is the energy (calories) expended — or the oxygen consumed — at rest; approximately 3.5 ml/kg/min.
An activity with a MET value of 8 means that the work rate required to sustain that activity is 8x greater than your resting energy expenditure.
METs allow us to classify the intensity of different activities, the advantage being that METs for any activity are the same for people with different weights, ages, and fitness levels.
In this case, METs would be the same for someone who’s 250 lb and 150 lb if they’re both running a 12-minute mile. However, heart rate would be a much better indicator of effort and intensity in this case, because the 150 lb person will be at a much lower intensity (heart rate) than the 250 lb person at the same absolute intensity. The 250 lb person will also burn more calories for the same MET intensity and duration vs. the person who’s 150 lb.
Running a 12-minute mile is approximately 8 METs, or equivalent to an oxygen consumption of 28 ml/kg/min.
For someone who’s 250 lb, oxygen consumption would be ~3.2 L/min.
From there, we can even calculate calories burned per minute (this is how all of the gym machines calculate “calories burned” during your workout…which you shouldn’t pay much attention to, by the way).
For every liter of oxygen we consume, we burn (use) about 5 calories.
3.2 L/min x 5 = ~16 calories per minute.
For the 150 lb individual running the same 12-minute mile, oxygen consumption is only ~1.9 L/min, and they’re going to burn ~10 calories per minute.
This just illustrates that METs are useful to gauge absolute exercise volume/intensity, but the relative intensity will differ greatly between two individuals with different BMIs.
Hypothetically, if someone only has a total of 2-3 hours per week to dedicate to structured aerobic exercise, how much of this 2-3 hours should be performed at an easy/conversational intensity, and how much should be spent at a higher intensity, to optimize fitness/longevity?
I love this hypothetical! There will be those who might disagree with me, but here would be my Rx and the rationale behind it.
There’s a lot of importance and hype (to use the word again) being placed on “zone 2 training” lately, and the importance of low-intensity exercise for health and longevity. While I’m not going to underscore the importance of this type of activity, I fear that we’ve lost sight of the fine line between prescribing exercise for elite athletes and prescribing exercise for the general population.
When time is limited, it’s my opinion that the time — in this case, time devoted to structured aerobic exercise — should be spent in the most optimal way possible.
In that case, I would say those 2-3 hours should all be spent above zone 2 (above “conversational” intensity”). There are data that vigorous-intensity exercise levels well above that are associated with reduced disease/mortality. Also, if we take the wealth of data that a higher VO2 max is associated with reduced mortality (and perhaps improved “longevity” however we might define it), then one will want to perform exercise that maximally stimulates improvements in aerobic capacity. The exercise that does that would be high-intensity interval training (HIIT).
2-3 hours of low-intensity exercise per week will not be enough stimulus (after a point) to increase VO2 max. Not to mention, in order to obtain the beneficial structural and functional cardiovascular adaptations of exercise, we also need a greater stimulus. This isn’t to say that light/moderate exercise isn’t beneficial — I’m purely speaking from the standpoint of someone who wants to optimize their 2-3 hours per week. Once someone has additional time to dedicate to aerobic training, I’d suggest sprinkling in some zone 2 work to “fill the gaps.”
I hope you found something practical and applicable in this week’s newsletter.
As always, thanks for reading.