The long-awaited summer is in full swing: warm weather, swimming pool visits, sunbathing on the balcony or in the garden, or simply a relaxing barbecue evening with friends and family. However, even at night, the temperature often "unfortunately" does not drop – the downsides of summer are slowly but surely becoming noticeable. For many, the hot temperatures – especially at night – often cause problems and disrupt their nocturnal rest. In this article, you will learn everything about sleep and how melatonin and tryptophan can influence sleep during the summer.
Table of Contents
Why is good sleep so important?
Sleep is a basic human need, and restful sleep means living better. We need it to relax and regenerate our bodies. During sleep, body functions run on standby: blood pressure, heart rate, and body temperature decrease. Cells undergo a repair process, blood sugar levels and hormones regulate themselves, and the immune system is strengthened. The brain also processes countless pieces of information and stores them. Unfortunately, we often only realize we lack sleep when our body simply runs out of energy and we are completely exhausted.
But how much sleep do we actually need? The National Sleep Foundation convened a panel to determine the optimal sleep duration based on scientific evidence. They concluded that 7–9 hours are sufficient for young adults and adults. 1
Comparing this with the results of a 2021 survey, the majority still fall below the recommended amount of sleep, as according to the survey, 68% of Germans sleep an average of 5-7 hours per night. 2 We should grant our body the rest it needs. After all, it is working at full speed around the clock.
Not only too little sleep, but also poor sleep can lead to the body's regeneration not proceeding as it should. This often manifests as memory problems, concentration difficulties, mood swings, fatigue, slowed reactions, stress susceptibility, and irritability. But the immune system and metabolism also suffer. You can recognize this by more frequent colds or weight gain, even though your eating habits have not changed.
Summer: What makes sleep difficult
In addition to already shortened and poor sleep, the hot summer and strenuous nights almost drive us to despair. We feel tired, but we can't close our eyes because it's stuffy, hot, and humid all at once. Even changing positions only helps for a short time. This situation is pure stress for the body. We cannot find rest and remain in a light sleep stage instead of entering deep sleep so that our body can regenerate.
In an interview with SWR, sleep researcher Hans-Günter Weeß answers the question of why heat makes us sleep so poorly with the following: "You have to know that sleep can only occur if we experience great relaxation on three levels - a mental level, an emotional level, and a physical level. Physical relaxation is the problem with extreme temperatures. This applies equally to heat and cold."
One way to combat this would be, "(...) for example, by taking a warm shower in the evening before going to bed. This opens the pores and allows the body to release heat better, and we feel colder," he adds. 3
Why we sleep worse in summer can have other causes besides heat. One of them is that it gets dark later and light earlier. As you may already know, the sleep-wake rhythm is dependent on light stimuli. Melatonin is important to prepare the body for nocturnal rest. Since the sun sets quite late in summer, melatonin production also occurs later. This can lead to many finding sleep later – and the falling asleep process is prolonged.
Time changes during travel can also significantly disrupt the sleep rhythm. This is called jet lag. This means that the internal biological rhythm does not match the time environment of the destination country. Here's a small example to better illustrate this: You start in Germany at 7 a.m. and fly for about 12 hours to Peru. Due to the summer time difference of 7 hours, you land there around 2 p.m. local time. In Germany, however, it would already be 9 p.m. This means tiredness – and that already at midday.
In this regard, it is all the more difficult to stay awake to sleep as usual at night. It takes some time for the body to re-synchronize with the current time zone. During this time, many suffer from sleep disturbances and problems.
Regulation of the sleep-wake rhythm
Melatonin – also known as the sleep hormone – is an endogenous hormone that regulates the sleep-wake rhythm. The melatonin level influences whether we feel tired or awake. As soon as it gets dark, the body produces melatonin, and our body can prepare for the night's rest. Bright light, on the other hand, inhibits melatonin production and signals the body to stay awake. The lower the melatonin content, the more tired we feel.
Melatonin also occurs naturally in numerous foods that can be consumed before going to bed. It can be found in the following foods:
- Nuts
- Bananas
- Sour cherries
- Pineapples
- Oats
- Flaxseed
- Milk
- Fish
- Eggs
- Tomatoes
L-Tryptophan is another hormone that is important for our circadian rhythm. While not directly responsible for melatonin production, it still plays a central role in its production. L-Tryptophan is converted into 5-HTP in the body. 5-HTP (5-hydroxytryptophan), in turn, is a precursor to serotonin, a neurotransmitter responsible for mood and sleep. To ultimately produce melatonin, the body draws on the mood hormone serotonin - and thus the circle closes. For the body to produce enough melatonin, there must also be enough serotonin. You can find out more about serotonin and its relevance for body and mood here.
L-Tryptophan can be found particularly in animal proteins, such as fish – especially salmon – eggs, seafood, nuts, and dairy products.
Melatonin and Tryptophan as supplements?
Melatonin is one of the most popular remedies worldwide for treating sleep problems. L-Tryptophan is also often used together with melatonin to improve sleep quality. But can melatonin and L-Tryptophan really help promote a restful and qualitative sleep, especially in summer? We would like to explain and discuss this based on the current state of research.
Studies on Melatonin
The first study we want to present to you dates back to 2022. This meta-study summarized randomized clinical trials to find out if melatonin has an influence on sleep quality, measured by the Pittsburgh Sleep Quality Index (PSQI). Adults with various diseases were examined.
The results showed that treatment with melatonin indeed has positive effects on sleep quality. However, this only applied to adults with respiratory diseases, metabolic disorders, primary sleep disorders, but not to those with mental disorders, neurodegenerative diseases, and other conditions. 4
Another study, which dealt with the aspect of sleep onset latency, found in an investigation of adults and children with diagnosed primary sleep disorders that melatonin has a significant effectiveness in shortening sleep onset latency and extending total sleep duration. Studies conducted over a longer period and also using higher doses of melatonin showed stronger effects regarding the shortening of sleep onset latency and the extension of sleep duration. Compared to placebo, the general sleep quality of the group taking melatonin improved. 5
A systematic review and meta-analysis showed that an earlier intake - 3 hours before the desired bedtime and a higher dose of 4 mg/day - could optimize the sleep-promoting efficacy of melatonin. The amount often used in clinical practice is 2 mg 30 minutes before bedtime. 6
Should you consider taking a higher amount of melatonin, we advise you to talk to your doctor about it. Furthermore, melatonin from 1 mg is only available with a prescription.
Studies on Melatonin and Jet Lag
Many people resort to melatonin when traveling long distances, as it plays an important role in regulating the sleep-wake rhythm. To substantiate this scientifically, randomized studies involving air travelers, flight personnel, or military personnel who were given oral melatonin and compared with placebo or another medication were used.
Nine out of ten studies found that melatonin helps with jet lag when taken at the right time. This means at bedtime at the destination, i.e., around 10 p.m. – midnight. If melatonin is taken at the wrong time, it can lead to daytime sleepiness and delay adjustment to time zones. In addition, doses between 0.5 mg and 5 mg help support sleep quality and fast onset of sleep. More than 5 mg should not be taken, as this does not increase the benefit. Overall, melatonin thus helps to reduce and prevent jet lag. 7
Studies on Tryptophan
Meta-analyses also showed, regarding L-Tryptophan, that supplementation with tryptophan can shorten wakefulness after sleep onset, which is an important factor for sleep quality. In addition, the group receiving ≥ 1 g of tryptophan had a shorter wakefulness after sleep onset than the group with less than 1 g of tryptophan supplementation. 8
Further interesting results were also provided by a study from 1979. This study examined how different doses of L-tryptophan affect people with mild sleep onset problems. The dose of 1 g significantly shortened sleep onset latency. Even smaller amounts showed positive results. A dose of 0.25 g was also sufficient to improve deep sleep. This is a very interesting observation, because we incidentally consume an estimated amount of 1/2 g to 2 g of tryptophan through our diet. 9
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Supplementation is not tackling the root cause
Apart from the studies mentioned, there are numerous other medical case studies and meta-analyses that confirm the effectiveness of melatonin and tryptophan in some cases – including for jet lag, travel, and temporary sleep problems. Nevertheless, it must be urgently added that this merely combats the symptoms, while the actual cause of the sleep problems remains unsolved.
To achieve long-term improvement, the existing problem must be identified and treated. This can often be psychological stress, anxieties about the future, etc. In urgent cases, we recommend consulting your doctor.
Further tips for better sleep in summer
In addition to melatonin and tryptophan-rich diet and supplements, we would like to give you further tips to finally turn your back on sleepless summer nights. The tips are simple, effective, and can be integrated into everyday life without much effort:
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Room temperature and sleeping environment
These two aspects are crucial for good sleep quality. A cool room temperature helps the body to lower its natural temperature during sleep. A cool temperature also signals to the body that it is bedtime. In summer, you can open the windows wide at night so that the slightly cooler air can come in. Fans also offer another option. Many also hang wet cloths on the fan to cool the air.
It is also important to darken the room, as light sources are disturbing and can hinder melatonin production.
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Avoid noise sources
What else can be disturbing besides bright light? Exactly: loud noises! Make sure that televisions, mobile phones, tablets, etc. are switched off in your sleeping environment to avoid unwanted background noise. If it is still noisy where you are, for example because you have loud neighbors, you can also use earplugs or ear defenders.
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Incorporate routines
Routines in everyday life, but also in the evening, e.g., bedtime rituals, can help to bring in some structure. This can calm and relax body and mind, as you already know what to expect. The brain knows: Now I can shut down, because it's slowly going into standby mode. This greatly supports the sleep rhythm and can counteract sleep problems.
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Avoid blue light
Blue light is also associated with disturbing the sleep-wake rhythm, as it interferes with melanin production. In addition, for many, it leads to eye and headaches, as the bright light is unnatural and difficult for the eye to focus. It is best to put your phone aside 2 hours before going to bed and treat yourself to some relaxing time.
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Bright light in the morning
Getting bright light in the morning helps to stabilize your rhythm and stimulate melatonin production. This prevents fatigue dips directly after waking up and ensures a fit start to the day.
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Light meal in the evening
Fatty and heavy-to-digest foods before bed are the real disruptor of good sleep. This is because the body is busy maintaining digestion and thus prevents the rest phase from occurring. The result: sleep problems and poor sleep quality.
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Supplements
Food supplements are ideal when it comes to gently guiding the body into sleep when certain circumstances such as jet lag or great summer heat do not allow it. Melatonin is now also available as sprays or in tea blends with additional herbs. But be careful: Melatonin does not combat the cause!
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Warm shower before bed
To prepare for sleep, the body lowers its natural body temperature. A warm shower before bedtime helps to widen the blood vessels in the skin so that the internal heat is released to the skin's surface. This supports the body's natural cooling, which is why you should definitely consider a warm shower before going to bed on hot nights.
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Always keep water at hand
Increased sweating at night makes you feel thirsty as your body loses a lot of water. A bottle of lukewarm water helps you stay hydrated.
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Napping
A short nap during the day (15-30min) can strengthen the body and restore cognitive performance. It is important that the nap does not last longer than 30 minutes, otherwise the body enters the so-called deep sleep phase. If you wake up and get up during this time, you often feel more exhausted and weaker than before.
Conclusion
Sleepless nights are and should not be a reason not to look forward to summer. After all, summer is the time when we are particularly active and social and should feel completely at ease. Nevertheless, hot nights and humid air can impair our sleep quality. With the right tips and the targeted use of melatonin and tryptophan, it is possible to successfully get through unbearable summer nights and enjoy the following day.
Sources
- Hirshkowitz M, Whiton K, Albert SM, Alessi C, Bruni O, DonCarlos L, Hazen N, Herman J, Adams Hillard PJ, Katz ES, Kheirandish-Gozal L, Neubauer DN, O'Donnell AE, Ohayon M, Peever J, Rawding R, Sachdeva RC, Setters B, Vitiello MV, Ware JC. National Sleep Foundation's updated sleep duration recommendations: final report. Sleep Health. 2015 Dec;1(4):233-243. doi: 10.1016/j.sleh.2015.10.004. Epub 2015 Oct 31. PMID: 29073398.
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Statista. (n.d.). Sleep duration of Germans. In Statista. https://de.statista.com/statistik/daten/studie/1277683/umfrage/schlafdauer-der-deutschen/
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Eich, S. (2023, July 10). Heat in summer: How we sleep well at night. SWR Aktuell. https://www.swr.de/swraktuell/radio/hitze-sommer-schlafen-koerper-getraenke-warm-duschen-100.html
- Fatemeh G, Sajjad M, Niloufar R, Neda S, Leila S, Khadijeh M. Effect of melatonin supplementation on sleep quality: a systematic review and meta-analysis of randomized controlled trials. J Neurol. 2022 Jan;269(1):205-216. doi: 10.1007/s00415-020-10381-w. Epub 2021 Jan 8. PMID: 33417003.
- Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013 May 17;8(5):e63773. doi: 10.1371/journal.pone.0063773. PMID: 23691095; PMCID: PMC3656905.
- Cruz-Sanabria F, Bruno S, Crippa A, Frumento P, Scarselli M, Skene DJ, Faraguna U. Optimizing the Time and Dose of Melatonin as a Sleep-Promoting Drug: A Systematic Review of Randomized Controlled Trials and Dose-Response Meta-Analysis. J Pineal Res. 2024 Aug;76(5):e12985. doi: 10.1111/jpi.12985. PMID: 38888087.
- Herxheimer A, Petrie KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev. 2002;(2):CD001520. doi: 10.1002/14651858.CD001520. PMID: 12076414.
- Sutanto CN, Loh WW, Kim JE. The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression. Nutr Rev. 2022 Jan 10;80(2):306-316. doi: 10.1093/nutrit/nuab027. PMID: 33942088.
- Hartmann E, Spinweber CL. Sleep induced by L-tryptophan. Effect of dosages within the normal dietary intake. J Nerv Ment Dis. 1979 Aug;167(8):497-9. PMID: 469515.
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