The Cost of Poor Sleep

Poor sleep can cost an athlete more than just feeling tired the following day. It can affect reaction time, concentration, decision-making and physical performance, making it harder to perform at the same standards. If training is designed to make you better, poor sleep can limit how well you recover, adapt and perform. Put simply, if you want to perform well, you must recover well.

Sleep is not 'rest' - The distinction between rest and sleep is determined by how much of the body is able to recover whilst this action is taking place. Rest allows the body to briefly recover from a physical workload, this means a conscious state of low activity. Sleep puts the brain in a very organised biological state where processes that aid in recovery, hormonal regulation, and immune function take place.

How does sleep affect reaction-time? What sets sleep apart from all other recovery methods is the cognitive rejuvenation that occurs when one is sleeping. As a result of bad quality or quantity of sleep, one's brain cannot process information, or anticipate what is happening or act to the best of its ability.

Do naps improve performance? In short, it depends. A study done in 2023 titled "Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials" concluded that 'After a night of normal sleep or partial sleep deprivation, a daytime nap between 30 and <60 min has a moderate-to-high effect on the improvement of cognitive performance and physical performance and on the reduction of perceived fatigue.' In this study the authors also acknowledged that 'Naps can be used to alleviate the effects of partial sleep deprivation'. This article goes into great detail about the length of naps and their corresponding effect of recovery, as it is considered a form of cognitive rejuvenation. Yet after a well-rested and quality night sleep, napping during the day would not have any substantial effect on the body's output. PS. they also prefaced that there needs to be at least an hour after awakening to relieve any sleep inertia brought on by the nap.

What improves sleep? In a 2023 article titled "Sleep physiology, pathophysiology, and sleep hygiene" what improves sleep was painfully simple, and not at all complicated to understand. Good sleep and consistent sleep are very intertwined, a consistent schedule allows the body to get better quality and duration of sleep. Evening exposure to bright and blue-light can suppress melatonin production and delay the body's instinct for sleep. Alcohol reduces sleep quality despite increasing temporary drowsiness. Large meals before bedtime disturb sleep as the body takes time and energy to digest the meal.

Sleep/ fatigue - Burnout is associated with poorer sleep quality, increased fatigue, and more physical symptoms, suggesting that prolonged psychological stress can impair recovery, immune function, and therefore overall physical health.

Decision-making and concentration - In a paper by Charest & Grander exploring the effects of sleep on physical performance. They explored athletes with; sleep duration, sleep quality, daytime sleepiness, fatigue, irregular sleep schedules and circadian disruption, and concluded that the cognitive abilities that are being affect include learning, memory, decision-making and creativity. This also means that lack of sleep affects how an athlete learns from training, not just how they feel the next morning. Creativity stood out to the authors as finding new solutions to changing situations in sport are negatively affected with lack of sleep.

Inflammation and immune function - Any athlete can create a substantial training load, but if sleep is consistently inadequate, the body may experience additional physiological stress rather than simply receiving the opportunity to recover from the training. In the same study they also found that lack of sleep can increase pro-inflammatory cytokines meaning potentially impairing immune function and recovery.

This provides an overall description on the cost of poor sleep yet the simplest fix was perfectly summarized in a 2023 study titled 'The Impact of Sleep Interventions on Athletic Performance: A Systematic Review' using 1,584 records said,

...it appears that increasing sleep duration at night or through napping was the most effective interventions to improve physical and/or cognitive performance.

Simply put, if an athlete feels that good sleep is what is holding them back, improving sleep should be treated as part of their training, as rest is not the same.

Below are the research papers used to get information for the article above, with links to their direct site.

Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials

Is daytime napping an effective...