Three Ways That Sleep Can Be Affecting Your Fitness

Three Ways That Sleep Can Be Affecting Your Fitness

When it comes to creating a balanced health routine, so many of us focus all of our attention on diet and exercise that we tend to neglect one crucial part… sleep. Inadequate sleep can wreak havoc on not only our health, but on our fitness result and performance too!

But what constitutes poor sleep? Well, according to the American Academy of Sleep Medicine, the average adult requires 7-8 hours of sleep each night to feel alert and well rested, although this number can vary from person to person (2). Poor sleep qualifies as not reaching these targets, and/or experiencing other issues such as having difficulty falling asleep, staying asleep, and not waking up refreshed. Poor sleep can be caused by ‘voluntary behaviour’, for example, binge-watching Netflix until 1am. ‘Involuntary’ causes of poor sleep include high workload or personal obligations, and medical or mental health problems such as sleep apnea, anxiety and insomnia.

Do you think a lack of sleep is affecting your workout? We have listed three pathways linking sleep deprivation with poor fitness outcomes.

1. You’re skipping gym sessions, or avoiding high intensity workouts
This one is a ‘no-brainer’. Sleep deprivation can reduce energy levels and motivation, making it extremely hard to get out of bed early for exercise, or detour to the gym after work. Which is a shame, because many studies have shown that exercise improves sleep quality and duration (3).

Even if you do make it to the gym, sleep deprivation is probably dictating your exercise choices. A review of scientific papers published in the Sleep Science medical journal explains that people suffering from sleep loss will preference tasks requiring less effort or exertion (4). So instead of going for a run, you may choose to go for a walk. Or, instead of working at 90% max during HIIT intervals, you work at 70% max or less. Whilst it’s ok to have a ‘slow’ day every once in a while, too many will see your fitness levels flatline or decrease, rather than improve.

2. You’re working hard, but your performance is slipping.
Did you know, lack of sleep can inhibit muscle repair and recovery post exercise, affecting your performance and ability to improve?

A study involving elite cyclists, conducted by the American Academy of Sleep Medicine, showed that max energy expenditure, max aerobic power and time taken to reach exhaustion decreased by 4%, 3% and 10% respectively when sleep was restricted to four hours a night (4).

3. Your nutrition and food choices take a nose-dive, affecting your energy levels

Lack of sleep can affect hormones controlling hunger and fullness (ghrelin and leptin), resulting in food cravings. People who don’t get enough sleep often crave sweet and fatty foods, as demonstrated by researchers from the University of Chicago. Their study involved phases of ‘normal’ sleep and ‘restricted’ sleep, and during the restricted sleep phase participants chose snacks that were 50% higher in calories, with twice as much fat. The study also commented that during the ‘restricted sleep’ phase, participants has trouble limiting their total snack consumption (5).

In addition, those who sleep less also report eating less fruit and vegetables, according to a study conducted by Stony Brook University of Medicine (6). Of course, after a poor night’s sleep, cooking a wholesome dinner is probably the last thing you want to be doing. What’s more, if you suffer from chronic lack of sleep, stocking the fridge with fresh produce (and consuming it before it perishes!) can be a struggle. Many poor-sleepers turn to Uber Eats for convenience, although most meals ordered are not particularly nutritious!

Poor diet can significantly affect your fitness. After all, the function of your ‘car’ is limited by the quality and quantity of fuel it has available!

What can you do?
If you can relate to one or more of these, and you have fitness goals to achieve, it may be time to focus on getting more Z’s each night. Good sleep hygiene involves ritual behaviours such as going to bed at a similar time each night, restricting stimulants such as caffeine and screen time, and/or practicing ‘calming’ behaviours such as reading or meditation. If you need advice on how to improve your sleeping habits, speak to your GP or specialist.