The Matt Walker Podcast Dr. Matt Walker

Today Matt’s discussion with  Dr. Craig Canapari continues, as they delve into the science behind sleep training. Together they cover what it is and when it may be an appropriate technique. Dr. Craig Canipari provides an overview of the different methods of sleep training - ranging from simple bedtime routines, to extinction  (also known as cry it out) - as well as some of the historical context behind the technique, and also the controversies and alternatives. It is such a personal choice, and different people feel comfortable with different methods. Dr. Canipari also discusses time restricted eating for your infant, and the importance of considering the long-term effects of sleep deprivation on parents.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way. 


The good people at InsideTracker are one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.


Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 benefits for anyone who uses the above link for their first order: 1) a discount on your order; 2) a one-year free supply of vitamin D; 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals, and biotics, together with essential vitamins. Matt’s been using it for several years now because he’s serious about his health, and because he did his research on the science and ingredients in Athletic Greens and thinks its scientific data can be taken as ground truth.


As always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.
Links for Dr. Canapari:
Book: https://a.co/d/07SDrVn  
Twitter: https://twitter.com/DrCanapari
Web: sleek.bio/canapari
TikTok: https://vm.tiktok.com/ZMemf3exT/
Instagram: https://www.instagram.com/drcanapari/
FB: https://www.facebook.com/CraigCanapariMd/

Today Matt begins a new series all about sleep in infants, in kids, in teenagers, and in parents. He is joined by Dr. Craig Canapari one of the world leaders in pediatric sleep medicine. Dr. Canapari  has also written a fantastic book on sleep for babies, kids and parents called, It's Never Too Late to Sleep Train. Enjoy the first episode in a new series, with some show highlights below! 


Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way. 


The good people at InsideTracker are one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.


 Today's podcast is also supported by biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. If you want to give LMNT a try, just head on over to drinklmnt.com/mattwalker and get your eight free samples with your first purchase. 
And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.


Links for Dr. Canapari:


Book: https://a.co/d/07SDrVn  
Twitter: https://twitter.com/DrCanapari
Web: sleek.bio/canapari
TikTok: https://vm.tiktok.com/ZMemf3exT/
Instagram: https://www.instagram.com/drcanapari/
FB: https://www.facebook.com/CraigCanapariMd/

On today’s episode, Matt goes beyond the if and the what type of exercise to discuss the when. Which is to say, does the timing of exercise matter when it comes to sleep improvements? Based on his experience working on insomnia, Matt would previously have recommended avoiding mid-to-late evening exercise as the resulting rise in core temperature could harm your chances for good sleep. However, it’s since been discovered that the evidence is quite the contrary, mostly allowing us to abandon the myth of evening exercise as the archenemy of good sleep.
But how late is late? How close to bedtime can exercise be done before things actually break? Studies have shown that exercise 3.5 hours before bed boosts sleep by fifteen minutes and significantly reduces the amount of time spent awake at night, while individuals who did weightlifting or resistance training two hours before bed fell asleep in half the time it would normally take and experienced an almost 20% boost in deep non-REM sleep in the first few hours of the night. Getting even closer to bed, an all-men study showed that neither cardio nor weight/resistance training ninety minutes before bed did any damage to sleep (though there was no marked sleep improvement either). But at sixty minutes, there was an impact—a reduction in the total amount and overall efficiency of sleep. Therefore, it seems that exercise before bed will more than likely result in very enviable sleep benefits, so long as it’s done more than an hour before bed (and ideally ninety minutes before).
In addition, it’s been discovered that exercising across different times of day can make a difference to the amount of at least three specific sleep features: REM sleep, light non-REM sleep, and time spent tossing and turning awake at night. First, exercising in the middle part of the day (i.e. three to eight hours before bed) is associated with moderately less REM sleep. Second, morning or evening exercise provides the nice benefit of spending less time in less-restorative, light non-REM sleep. And third, working out in the evening (at least three hours before bedtime) leads to more efficient sleep and less tossing and turning.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at InsideTracker are one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 benefits for anyone who uses the above link for their first order: 1) a discount on your order; 2) a one-year free supply of vitamin D; 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals, and biotics, together with essential vitamins. Matt’s been using it for several years now because he’s serious about his health, and because he did his research on the science and ingredients in Athletic Greens and thinks its scientific data can be taken as ground truth.
As always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Today, Matt focuses on how the type, intensity, and duration of exercise affect its impact on sleep. A study of middle-aged adults split its active group into three subgroups: moderate-intensity aerobic exercise, high-intensity aerobic exercise, and moderate-to-intense weight/resistance training. The groups performing aerobic exercise got more beneficial sleep effects, while surprisingly, the greatest improvement was in the moderate rather than the high-intensity group. These findings replicate those from the National Sleep Survey, indicating a Goldilocks syndrome in finding just the right level of exercise to benefit sleep.
Regarding types of exercise, studies show that cycling produces the most robust improvements in deep non-REM sleep. Meanwhile, more mind-body-based exercises provide equal if not greater benefits in sleep quality than traditional forms of physical activity. 
Another factor to consider is duration of exercise. Some studies have discovered that more minutes of acute exercise in a single bout produce larger benefits in several sleep metrics, including deep non-REM sleep, the speed of falling asleep, and the amount of sleep overall. However, it’s also been found that progressively longer bouts of exercise can be associated with a moderate reduction in the amount of REM sleep, though Matt states that it’s such a modest reduction as not to be concerning.
The final element is the intensity of exercise. Early studies found indications that more intense exercise gave a greater improvement in sleep quality, though the difference in improvement was minimal. Later, more comprehensive studies have reinforced this, indicating that it is not necessary to go to the extremes of physical exertion to get most of the sleep benefits exercise provides.
Currently, the reason why exercise promotes better sleep is unknown, but Matt offers several tenable possibilities, including that exercise promotes the release of immune factors and growth hormone. He also suggests a more “out there” explanation in the form of a chemical called brain-derived neurotrophic factor (BDNF), the release of which is facilitated by exercise, and which is known to increase deep non-REM sleep.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
Today's podcast is supported by InsideTracker, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link.  InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you. 
Another sponsor this week is the biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker. LMNT is an electrolyte sports drink that I can get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. If you want to give LMNT a try, just head on over to drinklmnt.com/mattwalker and get your eight free samples with your first purchase. 
And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

This week, Matt goes deeper into the relationship between sleep and exercise. More specifically, does daytime exercise change the stages and types of sleep? Deep sleep is critical for various functions, so anything that can increase it is desirable. Older adults have an inherently difficult time generating deep non-REM sleep; however, a study showed that the amount can shoot up by 40% following a day with modest exercise. Moreover, it indicated that participants’ cognitive functioning was significantly sharper following that night of exercise-enhanced deep sleep.
Exercise in healthy young adults also stimulates a lush increase in deep non-REM slow brainwave activity, up to 50% in the first part of the night. However, that exercise must be more vigorous to see a consistent, substantive, increase in deep non-REM sleep. 
However, there is a footnote to this good news: most of these studies saw a modest but reliable decrease in the amount of REM sleep the night following exercise. This isn’t a surprise for sleep scientists like Matt, who were already aware of some reciprocity between these two types of sleep, which seem to push and pull at each other’s levels. Why this reduction in REM sleep happens with a dose of acute, one-shot exercise and what the consequences are remains unexplored. Matt’s hypothesis is that it occurs because, in many of these studies, the total amount of time in bed is fixed. He suspects that if individuals were left to sleep as much as they wanted, they would sleep a little longer and thereby get the same amount or even more REM sleep.
Ultimately, the question becomes this: is regular exercise effective for maintaining and improving good sleep, or does its potency gradually wear off ? Thankfully, the answer is that regular, consistent exercise does benefit sleep, and the improvements it provides don’t get fade over time. Indeed, a meta-analysis approach teaches us that regular exercise has four persistent benefits, 1) improving sleep efficiency, 2) an increase in the amount of sleep achieved, 3) an increase in the speed of falling asleep, and 4) improvement in the quality of sleep experienced.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
The good people at InsideTracker are one of the sponsors of this week's episode, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link during the time window of this episode. InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
Also sponsoring this week are those fine people at Athletic Greens, and they are generously offering 3 benefits for anyone who uses the above link for their first order: 1) a discount on your order; 2) a one-year free supply of vitamin D; 3) five free travel packs. Athletic Greens is a nutrition drink that combines a full complement of antioxidants, minerals, and biotics, together with essential vitamins. Matt’s been using it for several years now because he’s serious about his health, and because he did his research on the science and ingredients in Athletic Greens and thinks its scientific data can be taken as ground truth.
As always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.

Does exercise have an impact on the quantity and quality of your sleep? The National Sleep Foundation's annual poll found that individuals who exercised frequently (defined as three times or more a week) reported sleeping with a higher quality than those who exercised less than once a week.  Exercise has also been shown to increase the release of endorphins, which can improve mood and promote feelings of relaxation, both of which can contribute to better sleep.
As with most things, moderation is key. Overexertion can have negative effects on sleep, so it's important to find a balance that works for you. It's also important to consider the timing of your exercise as engaging in vigorous activity too close to bedtime may make it difficult to fall asleep. On the other hand, some research suggests that low-intensity exercise performed in the evening can actually improve sleep.
Exercise has been shown to lead to longer sleep duration in both healthy individuals and those with sleep disorders, and it may also lead to improved sleep efficiency. One study found that moderate intensity exercise led to a 65% improvement in sleep efficiency, while another found that high intensity exercise resulted in a 34% improvement.
In addition to these benefits, exercise may also lead to deeper stages of sleep and a decrease in the number of awakenings during the night. A meta-analysis of 13 studies found that exercise was associated with an increase in non-rapid eye movement (NREM) sleep, specifically NREM stage 3 sleep, which is the most restorative stage. 
It's important to note that the relationship between exercise and sleep is not a one-size-fits-all scenario. The intensity, duration, and timing of exercise can all impact its effect on sleep. It's important to pay attention to your own body and its unique needs when it comes to finding the right balance of exercise and sleep. Additionally, the optimal amount and type of exercise for improving sleep may vary depending on a person's fitness level and individual preferences. 
It may be helpful to experiment with different durations and intensities of exercise to see what works best for you and your sleep patterns.
Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.
Today's podcast is supported by biochemical electrolyte drink company LMNT, and they are very kindly offering eight free sample packs when you purchase any one of their orders at drinklmnt.com/mattwalker.LMNT is an electrolyte sports drink that I can get behind - it's created from the basis of science, and it has no sugar, no coloring, and no artificial ingredients – all qualities that are so important to maintaining your blood biochemical balance. If you want to give LMNT a try, just head on over to drinklmnt.com/mattwalker and get your eight free samples with your first purchase. 
Another sponsor this week is the good people at InsideTracker, and they are generously offering a special 25% off any one of their programs for anyone who uses the above link.  InsideTracker is a personalized biometric platform that analyzes your blood and your DNA to better understand what's happening inside of you and also offers suggestions regarding things that you can do to better try and adjust some of those numbers, optimize them, and, as a result, optimize you.
And, as always, if you have thoughts or feedback you’d like to share, please reach out to Matt on Instagram.