Sleep: How it Affects Your Fitness Goals and What You Can Do to Improve It
Updated: Feb 17
As a coach in the fitness industry who works with many professionals who do not have the luxury of time, I often notice training and nutrition being treated as upmost priorities while sleep is swept to the side. I’m guilty of this too!
I chose this topic as my first blog post partly for a selfish reason as sleep as also the weak link in my own fitness lifestyle. Being in seasons where I was managing full-time academic coursework, a position at a students’ union, and handling clients as a personal trainer, my sleep has often suffered. During these periods, it would often be the case where my only option would be to keep my performance in the gym from regressing.
I think this is especially prevalent in the North American professional world where we value hard work and making sacrifices to further our career development, even if those sacrifices include sleep. While the Canadian 24-Hour Movement Guidelines for Adults, released in October 2020 recommend 7 – 9 hours of sleep for adults aged 18 – 64, with the average adult Canadian meeting these guidelines, poor sleep hygiene (namely poor bedtime routines and a lack of a consistent sleep schedule) are still common (1).
Not only do a large proportion of us fail to establish healthy bedtime routines and a consistent sleep schedule, it also been found that we have a poor ability to self-assess our own sleep duration and quality (2), suggesting that us gym-goers with a lot of other commitments on our plate may not be sleeping as much as we think!
In this article I’ll go into detail on how poor sleep can impact adherence to our diet and training. Lastly, I’ll go into some detail on a variety of different methods that can improve our sleep, whether we have the time to sleep 8 hours or not.
Why should we care about sleep?
So… why should we even care about sleep and what are some of the consequences that can arise if we decide to skip a couple hours of bedtime? While covering all the possible ways in which poor sleep might negatively impact our progress in the gym goes beyond what I can cover in a blog post, I wanted to
touch on the psychological aspect, specifically in terms of adherence to our diet and training regimens. Those I work with are normally 0 to 1 year into their fitness journey and one of the most important things I try to establish early on with my clients is establishing a routine where the gym and healthy nutrition habits are a normal part of their daily lives. Sleep has a direct impact on this.
Sleep and training adherence
One way in which poor sleep can negatively impact our training is by increasing our levels of perceived effort in the gym. Let's say for example, your max set of 10 on the squat is with 200lbs. On a given day in which you are fully recovered from previous training stress with sufficient sleep the night prior, then you would likely perceive that you had 3 reps left in the tank if you completed a set of 7 with 200lbs. All else being equal, let's say you only slept 4 hours the night before your squat session and you try that set of 7 with 200lbs.
This time, you may think you could have only completed 1 extra rep. This is what is meant by increased perceived exertion… Putting in effort feels WORSE when you are sleep deprived. One likely answer for why sleep increases perceived exertion is that the availability of energy resources affects our body's ability to expend effort.
Glucose metabolism is one way that energy is released. Leproult and colleagues (3) found that 24 hours of total sleep deprivation reduced glucose metabolism and increased perceptual effort. Another study found that sleep deprivation and 48 hours of continuous work increased perceived exertion and subsequently decreased the walking pace of participants (4).
Now that you know that losing sleep can reduce your ability to put in effort, what kind of effect does this have on the quality of our training?
One of the most important principles to consider when designing your training program, ranked only behind the specificity principle, is Progressive Overload. The definition of Progressive Overload has two parts: the first is that training must be sufficiently challenging for you to make progress. The second states that training needs to get progressively more difficult to continue providing the stimulus required to make progress. If poor sleep increases perceived exertion, this poses problems for meeting this definition when you are training in the gym because you may be unable to complete sufficiently challenging sets to meet the criteria for Progressive Overload.
Sleep and diet adherence
Sleep also affects diet adherence. When you are sleep deprived, there is a physiological cascade of events that occur as a response to a depletion of resources, which make you crave calorically dense foods to make up for this loss in energy. For example, Spiegel and colleagues found that limiting 2 nights of participants’ sleep to 4 hours per night increased Ghrelin, a hormone that stimulates appetite) by 28% and decreased Leptin, a hormone that suppresses appetite) by 18% (5).
Indirectly related to sleep, the act of exposing yourself to certain social scenarios late at night has the potential to derail you from making healthy decisions, making it harder to adhere to your diet later in the evening (6). Another potential explanation may be that our ability to regulate the choices we make is limited in capacity (7).
The majority of us are well aware that the times when our discipline is tested the most is during late nights out on the weekend. Over the course of a night out we are constantly inundated with comments such as “just have one drink” and “one bite won’t kill you!” As the night progresses, our ability to self-regulate and say “no” to these statements diminishes. This may be a reason why evening chronotypes (night owls) delay bedtime, often times for evening activity have worse health behaviours such as greater alcohol consumption than their early bird counterparts (6; 8). This is one reason why it may be a good idea to hit the hay a night early!
How can we improve our sleep?
So, now that we know that losing sleep can negatively impact our perceived effort during training and adherence to our diet, here are some strategies to help you improve your sleep.
A good night's rest is dependent on four elements related to our sleep. If any one of these are negatively impacted, our sleep is compromised and we won't be getting the best night's sleep that we could be.
The four pillars of sleep refer to (9):
Duration simply refers to the total length of time spent asleep; quality refers to whether your sleep is restful and restorative; continuity refers to how long you can stay asleep without interruption and regularity refers to whether you go to bed and wake up at similar times. Each of the strategies that will be discussed shortly works to improve one or more of these pillars.
Tip 1: Make sleep your priority
This tip is more anecdotal, and it simply comes down to building a schedule around your sleep instead of trying to fit sleep into your schedule.
When creating this schedule, the first thing you should be doing is blocking off a certain amount of time that you are devoting to being in bed and then adding items to your schedule from there. In doing this, it’s helpful to be realistic and understand that you can only fit so much onto your plate before your self-care starts to suffer.
If you have assessed your schedule and realized that there are simply too many commitments for you to get an adequate duration of sleep, then you may need to think about dropping something in your schedule to make up time.
I do realize that a lot of us out there simply do not have the luxury of adjusting our schedule to improve our sleep duration, so these other strategies can help you improve your sleep even without time being on your side.
Tip 2: Go to bed and wake up at roughly the same times
Your body contains an internal clock called your circadian rhythm. It is the main player when it comes to changes in behaviour that occur in a rhythmic pattern. When we approach the later hours of the day in which bright light is not as present, our body secretes melatonin, causing us to feel tired.
However, during the day when we are exposed to bright light, our body does not secrete as much melatonin (10). To keep in line with our body's circadian rhythm, it is best practice to go to sleep and wake up at roughly the same times as it has been shown to aid in long term sleep quality (11).
Tip 3: Have a bed-time wind-down period
Even stress from our every day lives can result in those with insomnia to develop sleep anxiety (12). I've been there before. Anxious about about exams and presentations to following day and wondering whether I'll be restless that night. The most useful suggestion I can make would be to cease all work and other stress-inducing activities at least 1-hour before bedtime to give yourself a chance to unwind and relax before bed. This 1-hour time block is your “bed-time” routine.
Here are a few, pointers for what to incorporate into your bed-time routine:
Your bedtime routine should start at the same time every day to improve the regularity of your sleep schedule.
Try to do something completely unrelated to your work life, such as reading a book or finding a playlist that helps you fall asleep.
Avoid blue light emitted from cell phones, laptops, TVs and other devices.
Tip 4: Increase bright light exposure during the day
Remember in tip number 2 how I explained that melatonin secretion causes us to feel tired and that it’s suppressed when we are exposed to bright light? For this reason, it’s a good idea to expose yourself to bright light during the day to keep your circadian rhythm in sync. Campbell and colleagues (13) determined that sleep in those with insomnia significantly improved in response to timed exposure to bright light in terms of reduced waking time within sleep and improved sleep efficiency.
Tip 5: Avoid blue light exposure at least 2 hours before bed
Blue light can also suppress melatonin secretion. If this occurs at night, it can disrupt our circadian rhythm, causing us to feel awake and tired at irregular times (14). Since blue light suppresses melatonin, limiting your blue light exposure before going to bed would be helpful. This means avoiding televisions, smartphones, tablets, and other electronic devices at least 2 hours prior to going to bed.
While these do have an option in the settings feature to switch the display from emitting blue light to emitting orange light, it does not completely protect us from melatonin suppression. If you need to keep looking at your screen during the hours leading up to bedtime, a solid alternative would be to opt for blue-light-blocking glasses!
Tip 6: Keep your bedroom cool
We sleep best in cool environments. A study by Okamoto-Mizuno and colleagues (15) showed that mild heat exposure decreased sleep quality and increased wakefulness. Set your thermostat at a temperature that you feel comfortable sleeping at, for most people this is 70 degrees Fahrenheit or 20 degrees Celsius.
Tip 7: Avoid alcohol and stimulants such as caffeine
Besides the fact that alcohol has been shown to interfere with the anabolic processes essential for muscle growth, research has shown that heavy alcohol users have reduced rapid eye movement (REM) sleep. Sleep is split into four different stages. REM stage sleep typically takes place 90-minutes after the individual falls asleep and is thought to be where your most vivid dreams take place.
It is also thought to be necessary for restoring the mind and providing it with the needed energy during waking hours (16). For this reason, I believe that lack of REM sleep may contribute to a person’s decreased ability to stick to their training and diet. And even though the time it takes for an individual who’s consumed alcohol to fall asleep is less, it takes longer for that individual to enter REM sleep (17). This explains why we don’t feel well-rested after a night of drinking, even when we sleep over 8 hours.
In terms of caffeine intake, caffeine and other stimulants enhance energy by stimulating our sympathetic nervous system; this is also known as our fight or flight response. We want to be in a parasympathetic state when we sleep. Because caffeine stays in the bloodstream for 6-8 hours, we should aim to stop our caffeine consumption ideally 8 hours before bed.
Tip 8: Supplement with these…
As a preface, I generally don't think supplements should be introduced until lifestyle factors are addressed first for a couple of reasons... In my experience, if sleep issues are caused by poor lifestyle habits, such working on your laptop into the late hours of the night and then immediately going to bed, supplementation alone likely won't fix the issue. Supplements by definition, serve to enhance what is already present! This is why I did not introduce supplementation until last in this blog. I wanted to leave you with the tips above first and then introduce supplements as an additive component to the lifestyle practices I mentioned.
Zinc and magnesium: probably my two most recommended supplements would be zinc and magnesium. Zinc assists in the metabolism of melatonin, so if you are supplementing with melatonin, I would recommend adding in zinc in as well. In addition, magnesium and zinc are two minerals that have been shown to have a sedative effect on the nervous system and their effects have been studied on patients with insomnia, with researchers reporting beneficial effects on sleep quality (18; 19).
Ginkgo biloba: Is a natural supplement that is supposed to aid in sleep and has been shown to improve the cognitive performance in older adults. A study by Hemmeter and colleagues (20) showed that gingko biloba improved sleep efficiency and reduced the number of times people woke up in the middle of the night.
Ashwagandha: Like ginkgo biloba, ashwagandha is another natural supplement that has been studied as an alternative treatment for insomnia. One study by Langade and colleagues (21) showed significant improvements in both participants with insomnia and without insomnia.
L-theanine: L-theanine is an amino acid that is known to help with relaxation, helping us fall asleep faster and thereby improving total sleep duration. The effectiveness of L-theanine as a sleep aid has been tested in a randomized, double-blind, placebo-controlled trial containing boys diagnosed with ADHD. The L-theanine group was found to improve sleep duration and efficiency compared to the control group (22).
You'll notice that I didn't include melatonin supplementation in here, which seems like a no-brainer, given how important serum melatonin levels are for keeping your circadian rhythm in sync. I do think melatonin can be beneficial but when used sparingly and in low doses (1 - 2mg). This is a topic for a completely separate blog post since I want to talk about it in more detail!
With all of the negative effects of poor sleep that are currently known in the research literature, If I could leave the busy professional with any lasting thoughts, it would be to not leave sleep as your last priority.
Ultimately, it affects every other tool at your disposal to improve your body composition and performance, so it should be treated as a foundation. While this may seem contrary to what a lot of people practice, I would rather someone sleep in an extra 2 hours than try to fit in that 6th workout of the week before work. It’s one of the most important variables to aid in your recovery from training… Treat it as such!
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