How many hours of sleep? How much sleep do you need?

Sleep is one of the body's basic regenerative processes, and its course depends on daily habits. It is increasingly being pointed out that the number of hours alone does not give the full picture, as the body responds primarily to the regularity and proper timing of sleep in the circadian rhythm. It is the moment of falling asleep, the quality of the transition between phases and the stability of night-time rest that can determine regeneration to a greater extent than individual differences in the length of sleep.

1. The right amount of sleep
2. Taking care of the quality and quantity of sleep
3. Bedroom conditions and other factors
4. Eating before bedtime
5. Sleep supplements

The right amount of sleep

Analyses of research involving millions of people have shown that healthy adults should sleep around 7-8 hours a night. This is the amount of sleep needed to feel good every day and avoid long-term health problems. In one of the largest reviews, which gathered over 4.4 million participants from different countries, this range of sleep was associated with the best overall health and a lower risk of chronic diseases.

When we sleep less or more...

Studies observing people who slept less than 7 hours showed a higher incidence of metabolic problems, higher blood pressure, weakened immunity and poorer mental well-being. At the same time, some data indicate that very long sleep, exceeding 9 hours, is also associated with less favourable health indicators, especially in the area of cardiovascular disease and metabolic disorders.

Our age and sleep

Analyses of different age groups have not found that age significantly changes the biological need for sleep, with differences relating more to the architecture and regularity of sleep than to the number of hours slept. The publications also emphasised that, in addition to the duration of sleep, its quality, a stable circadian rhythm and conditions conducive to regeneration are also very important, as illustrated by reviews describing the impact of sleep restriction on physical and mental functioning.

"Melatonin is a hormone produced naturally by our body. It is produced by the pineal gland, but is also found in other areas. It is often called the sleep hormone because it helps us fall asleep." Agata Bugorska - Dietician

Taking care of the quality and quantity of sleep

Research on sleep hygiene has shown that the most important thing is to maintain a consistent bedtime and wake-up time, as a stable circadian rhythm helps the brain transition into deeper stages of sleep. Light is very important, so it is a good idea to use natural lighting during the day and limit your eyes' exposure to screen light in the evening, as this can delay sleep. A calm evening routine also helps to reduce nervous system arousal and prepare the body for sleep, including meditation or breathing techniques.

Bedroom conditions and other factors

Bedroom conditions are very important for good sleep. Ensure that the room is well ventilated and completely dark. The literature also points out that the bed should be associated exclusively with sleep, not with work or screens, which reduces tension and helps to calm the mind. Regular physical activity is another factor that supports healthy sleep, but too intense training too late in the day can make it difficult. Caffeine consumed in the afternoon, heavy meals just before bedtime and alcohol can also disrupt the quality of sleep, especially deep sleep.

Hormones involved in sleep regulation

Eating before bedtime

Studies on nutrition and sleep have shown that an evening meal works best when it is light and based on products that facilitate the production of melatonin, the so-called sleep hormone. Protein products containing tryptophan (which is converted into melatonin), including dairy products and eggs, usually work well. It is worth including carbohydrates with slower absorption kinetics, such as oatmeal or rice, in combination with fruits that contain substances that promote sleep regulation, such as kiwis or cherries.

Sleep supplements

Among dietary supplements with the best-documented effects, melatonin stands out. In controlled studies, it has been shown to help regulate the circadian rhythm and is effective in treating jet lag and sleep phase disorders. Magnesium can promote relaxation and improve sleep quality in people with low intake and high exposure to exertion and stress. Among plant extracts, valerian, hops and lavender have been most frequently described as having a mild tension-reducing effect and facilitating sleep. L-theanine from green tea is sometimes associated with a calmer transition to sleep, especially when difficulties are caused by stress.

Sources:

• Chaput, J. P., Dutil, C., Featherstone, R., Ross, R., Giangregorio, L., Saunders, T. J., Janssen, I., Poitras, V. J., Kho, M. E., Ross-White, A., & Carrier, J. (2020). Sleep duration and health in adults: an overview of systematic reviews. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 45(10 (Suppl. 2)), S218–S231. https://doi.org/10.1139/apnm-2020-0034
• Jike, M., Itani, O., Watanabe, N., Buysse, D. J., & Kaneita, Y. (2018). Long sleep duration and health outcomes: A systematic review, meta-analysis and meta-regression. Sleep medicine reviews, 39, 25–36. https://doi.org/10.1016/j.smrv.2017.06.011
• Watson, N. F., Badr, M. S., Belenky, G., Bliwise, D. L., Buxton, O. M., Buysse, D., Dinges, D. F., Gangwisch, J., Grandner, M. A., Kushida, C., Malhotra, R. K., Martin, J. L., Patel, S. R., Quan, S. F., & Tasali, E. (2015). Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep, 38(6), 843–844. https://doi.org/10.5665/sleep.4716