Summer may be the best season for traveling and enjoying the hot weather, but if you do not have an AC unit, getting a good night's sleep can seem impossible.

The Sleep Foundation says that heat can severely interfere with your body's thermoregulation abilities, which can make you feel physically and mentally tired, and unable to fall asleep. They suggest the best temperature for sleep is approximately 65 degrees Fahrenheit (18.3 degrees Celsius).

The exact number can vary by a few degrees from person to person, but doctors recommend keeping your bedroom temperature around 60 to 67 degrees Fahrenheit (15.6 to 19.4 degrees Celsius) in order to get the most comfortable sleep.

Newsweek spoke to an expert and gathered the top tips on how you can get the best night's sleep during a heatwave, or if you do not have air conditioning.

Dr Andrew Varga, MD, neuroscientist, and physician at The Mount Sinai Integrative Sleep Center, told Newsweek that extremes of either temperature can make it difficult to sleep, but sustained heat, in particular, can be a problem, since it is normal for the body's temperature to drop during sleep.

He said: "There is some thought that this body temperature drop is required to enter the deepest stage of non-REM sleep, e.g. stage 3 or slow wave sleep."

According to the Sleep Foundation, this is because, during REM sleep, the body ceases most temperature-regulation behaviors, such as sweating or shivering, leaving you more sensitive to temperature changes.

Dr Guy Meadows, co-founder and clinical lead at Sleep School, believes our core body temperature plays an important role in the regulation of sleep. He told Newsweek that at the start of the night, a 1°C drop in temperature is needed to help you fall to sleep.

"It's this decrease, coupled with the arrival of darkness, that informs the internal body clock that the night has begun. This triggers the release of the sleeping hormone melatonin, helping you to fall into sleep," he said.

Troubles sleeping will most likely cause you to feel tired and sleepy the next day, which can negatively affect your daily routine. But, there are some things you can do to help the quality of your sleep.

Varga suggests that brief exposure to heat, like taking a hot shower or bath before going to bed, can help.

He said: "The heat from the bath/shower will vasodilate your periphery (arms/legs), which thereby draws blood away from your core and helps lower one's core body temperature; the lower core body temperature being the factor that helps aid with deep sleep onset."

A research team from the department of biomedical engineering at The University of Texas at Austin found that bathing one to two hours before bedtime in water at 104 to 109°F (40 to 43°C) helps people get the best quality sleep, and can help you fall asleep an average of 10 minutes quicker than normal.

According to Meadows, getting frustrated and restless because you're too warm only makes your body generate more heat, keeping you awake for longer, so he suggests keeping a cool head by lying still, accepting the heat.

He said: "Try this, focus your attention on the discomfort and describe what you feel objectively and without judgment such as 'I feel heat and sweat on my face, neck, and back.' Learning to change your relationship with the heat helps defuse its power and lead to better sleep."

Another suggestion is using a fan and sleeping in a side position, which according to Varga, is likely to maximize the body surface area exposed to air, to help dissipate the heat.

The Sleep Advisor blog says that sleeping with a fan on is good for a number of reasons. It helps control the temperature in the room, and stops you from sweating, especially if you have a memory foam mattress, which tends to overheat.

Using a fan also helps air circulation, which boosts the room's freshness and battles stagnancy, eliminating stale and heavy odors due to low airflow.

However, this alternative is not for everyone, some people get allergic reactions or sore muscles among other downsides, and Sleep Advisors suggests sleeping with a fan only if you get hot during the night.

Your sheets can also impact your body temperature, so choosing sheets that don't retain heat and help to dissipate sweat is key to helping you sleep.

Breathable bedding materials renowned for their moisture control include cotton, tencel, rayon derived from bamboo, and silk.

Hot air rises, so if you have space aim to sleep downstairs suggested Meadows, or move your mattress to the floor.

Dr Meadows suggests using blankets and sheets, rather than a single duvet. He said: "Layering bedding so that blankets and sheets can easily be taken off or put on during the night can make body temperature adjustment easier."

Regardless of room temperature, in order to get the best possible night's sleep, you should lose some bad habits that can undermine the quality of your sleep.

Dr Varga suggests avoiding the use of electronics in bed, or even before sleeping in general. According to the Cleveland Clinic, scrolling down your phone at night distracts you, and engages you, which makes it harder to fall asleep.

Since the blue light from your phone is an artificial color that mimics daylight, exposure to it can affect your internal body clock and throw off your circadian rhythm, which is usually in tune with light and dark.

While exercising is a great practice to stay healthy, and a light evening exercise can help get you tired enough to fall asleep, you should avoid any intensive exercise before bed.

According to the Sleep Foundation, exercising intensively during the three-hour period leading up to bedtime can negatively impact the quality of your sleep, and that's because intense training can increase your heart rate, body temperature, and adrenaline levels.

Varga also suggests avoiding food and alcohol at least three hours before sleep. Since alcohol can reduce REM sleep, people who drink before bed often experience insomnia after drinking and feel excessively sleepy the following day.

Alcohol also contributes to sleep apnea because it causes the throat muscles to relax, which in turn creates more resistance during breathing, leading to disruptive breathing episodes.

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