Fitness and Fatigue

Are you making the progress that you would like to in the gym? Does it seem hard to stick with your diet? Are you having trouble focusing on work and completing tasks? If so, fatigue maybe hindering you in several areas of your life! But what can you do about it? In this essay, I’ll define fatigue, discuss things that contribute to it, and make some suggestions about how to minimize its effects on you.

               Fatigue is a response to sleep loss or extended mental or physical exertion. Fatigue and sleepiness are related, but not the same thing. Sleepiness is the propensity to fall asleep and a major contributor to lapses in judgment. In general, fatigue leads to poor task performance and increases the likelihood of injury. General fatigue can be broken down into several subcategories: cognitive fatigue, physical fatigue, burnout, emotional fatigue, visual fatigue and vocal fatigue.(1) You may have felt some or all of these things at some point in your life, and here I’m going to focus on a few of them and how they might detract from your fitness goals.

               Fatigue has many contributing factors, which can be divided into two groups: intrinsic and extrinsic. The intrinsic factors are sleep deprivation, circadian alignment, the quality of sleep (called ultradian process), sleep homeostasis (time spent awake vs asleep), and health factors like sleep disorders, medications or drugs, emotional dysregulation, and injury. Extrinsic factors include workload, performing shift work, and environmental factors like noise, light, temperature or other things that disrupt sleep.(1) When you have one or more of these contributing factors, you will find yourself in a state of fatigue, which leads to negative outcomes in many areas. Although the extrinsic factors for fatigue detract from your wellbeing, the intrinsic factors associated with sleep are my main focus here. Basically, if you are not sleeping enough, or experiencing poor quality or interrupted sleep, you are going to begin to feel fatigued and your fitness goals will suffer.

               Let’s look at physical performance first. Although some of the research shows that there is no physiological decrease in performance due to fatigue, there are psychological decrements that alter your perception of the task; when you are sleep deprived, lifting the same weight that you usually do can feel more difficult and cardio sessions can be perceived as taking longer than normal. And it’s not just sleep loss that can bring about this effect, feeling burned out or emotionally drained from work can limit your ability to perform at your peak as you might not have the mental energy to dedicate to training. Sleep is when we recover from our day and any exercise we have performed. This recovery comes in two forms: neurological as our nervous system gets time to rest, develop connections for new motor patterns and replenish neurotransmitters, and muscular as our bodies replenish the spent energy stores in the muscles. If you have not had adequate sleep during your next workout, you may feel that you tire more quickly when exercising, limiting your performance. (2)

               When it comes to your goals of weight loss, you may not think that sleep and fatigue have much to do with it, but their interconnectivity is surprising. Sleep deprivation effects two very important things that can make sticking to a diet difficult. The first is that not getting enough sleep changes how your brain responds to food. You may not feel hungry, but your brain will make food much more desirable. This happens because several areas of your brain that help you make food choices are less active, and there is more activity in the area that makes getting food seem more important. Second, when you are sleep deprived, you will crave foods that have a higher caloric density. Additionally, the more sleep deprived you feel the stronger the craving for high calorie foods! So not only will you want food more when sleep deprived, but the food you want will be more likely to cause weight gain. (3)

               So what is someone to do about all these negative impacts of sleep deprivation and fatigue? The main thing is to try your best to increase the duration and improve the quality of your sleep. To do this, make sure your bedroom is cool and dark, and limit your exposure to screens before bedtime. I would recommend setting your alarm and putting your phone away and turning the t.v. off an hour before bed. This also gives you time to process your day and let go of any lingering thoughts that you have. It is common that when someone lays down in bed to rest their mind will begin racing. Giving yourself some quiet time before bed can allow those thoughts to be processed before trying to get to sleep; write down any to-do list items for the next day and let go of any stress from work you may be feeling. Avoid drinking alcohol or using THC products before bed, as those psychoactive substances can interfere with your ability to get into deep sleep, a crucial time in which your brain detoxifies, and many essential hormonal processes are carried out. Changing your pre-sleep routine and habits can be hard, but it is worth it. Being well rested will help you exercise harder and make better food choices, both of which will benefit your health for many years to come!

Sources:

1) Graham Marvin, DPhty, CSCS, Ben Schram, PhD, Robin Orr, PhD, and Elisa F. D. Canetti, PhD. Types and Contributors to Occupational Fatigue. NSCA Strength and Conditioning Journal, August 2024, Vol. 46, Number 4. Pg. 500-509

2) Charest J, Grandner MA. Sleep and Athletic Performance: Impacts on Physical Performance, Mental Performance, Injury Risk and Recovery, and Mental Health. Sleep Med Clin. 2020 Mar;15(1):41-57. doi: 10.1016/j.jsmc.2019.11.005. PMID: 32005349; PMCID: PMC9960533. https://pmc.ncbi.nlm.nih.gov/articles/PMC9960533/#S13

3) Greer SM, Goldstein AN, Walker MP. The impact of sleep deprivation on food desire in the human brain. Nat Commun. 2013;4:2259. doi: 10.1038/ncomms3259. PMID: 23922121; PMCID: PMC3763921. https://pmc.ncbi.nlm.nih.gov/articles/PMC3763921/#S1