Sleep is a period of reduced mental and physical activity and is associated with a typical posture in humans, such as lying down with eyes closed. Sleep results in a decreased responsiveness to external stimulation. Sleep is a state that is relatively easy to reverse; this differentiates sleep from other states of reduced consciousness, such as coma. It is something we do daily, or ought to be doing, without too much effort. What we don’t realize is how important it is for weight management; it could even be called the secret weight management weapon. Good sleep improves your brain performance, mood, and health. Not getting enough quality sleep on a regular basis raises the risk of many diseases and disorders ranging from heart disease and stroke to obesity and dementia.
Why is sleep important?
Sleep is influenced by our circadian rhythms therefore it is important to understand what circadian rhythms are – the physical, mental, and behavioural changes we experience over a 24-hour cycle. Light and dark have the biggest influence on circadian rhythms, but food intake, stress, physical activity, social environment, and temperature also affect circadian rhythms, and therefore sleep. During sleep, your body is working to support healthy brain function and maintain your physical health. In children and teens, sleep also helps support growth and development. Here’s how sleep affects various body systems and the importance of getting enough sleep:
Heart and circulatory system: When you sleep, you cycle through two phases of sleep: rapid eye movement (REM) and non-REM sleep. During non-REM sleep, blood pressure and heart rate decrease, giving your heart a break from its daytime exertions. In contrast, during REM sleep and waking, the heart rate and blood pressure increase. Insufficient sleep or frequent awakening during sleep can increase the risk of coronary heart disease, high blood pressure and stroke because the heart and cardiovascular system do not get enough “break time”.
Metabolism and sleep: Circadian clocks in various organs, including the liver, fat, and muscle, regulate how the body processes fats and other nutrients. Adequate sleep, particularly during the deep sleep stage, is crucial for energy restoration, muscle repair, immune function, and energy production regulation. Sleep may influence the cellular structures responsible for converting food into usable energy. Sleep deprivation can disrupt these processes, leading to:
- Higher level of the hunger hormone ghrelin and lower level of the appetite supressing hormone leptin. You can read more about this here.
- Reduced insulin sensitivity
- Increased cravings for unhealthy foods
- Sluggishness and decreased physical activity
These factors contribute to weight gain and obesity.
Cognitive function, mood and motivation: Sleep is crucial for learning and memory consolidation. Inadequate high-quality sleep can impair focus, clear thinking, and the ability to perform daily tasks effectively, including driving and schoolwork. Sleep is essential for emotional regulation. It helps store memories and process feelings. Sleep deprivation is linked to mood disorders, depression, and stress-related conditions, which can diminish motivation for activities like exercise. Depression and weight gain are interconnected through metabolic disturbances and inflammation, but adequate sleep can help mitigate these issues.
Understanding how sleep impacts these and other body systems highlights the importance of adequate sleep in terms of both time and quality. To maximize the benefits and minimize the risks, follow sleep guidelines: maintain a consistent sleep schedule, create a relaxing bedtime routine, limit caffeine and large meals before bed, manage light exposure, and ensure your sleep environment is conducive for rest. These guidelines are detailed here.
Resources
- General resource on sleep
- Sleep Stages and Phases
- Circadian rhythms
- What happens in the brain when we sleep?
- Why Sleep is Important
- Are We “Brain Washed” during Sleep?
- Discovering the Brain’s Nightly “Rinse Cycle”
Dr. Acham Hedwig is a distinguished Senior Lecturer in the Department of Food Technology and Nutrition. Holding a Ph.D. in Nutrition, she focuses on innovative strategies to enhance public health through improved nutrition. Dr. Hedwig's research delves into the nutritional value of food products and dietary interventions, assessing their impact on health outcomes and educating the masses about good nutrition. Beyond her academic duties, Dr. Hedwig collaborates actively with industry partners and health organizations, translating her research into practical applications. This commitment to bridging academia and industry has significantly enhanced the real-world impact of her work, particularly in improving nutritional standards and promoting healthier eating habits.
Zenah Nantumbwe
Contributor
BA Industrial and Organisational Psychology (Mak); MSc Clinical Psychology (Mak)
Wellness Psychological Services
@wellnesspsychug
Yvonne Zabu
Contributor
BA Psychology (Nelson Mandela University); HonSocSci Psychology (UCT); MSc Clinical Psychology (Mak)
Wellness Psychological Services
@wellnesspsychug
