Here's something to try to beat that night-time heat – and which might also be good for your brain.
Swiss scientists say the gentle rocking motion of your backyard hammock can bring us broad benefits for sleep – including boosting memory consolidation.
Laurence Bayer and colleagues at the University of Geneva Bayer had earlier shown how continuous rocking during a 45-minute nap helped people to fall asleep faster and sleep more soundly.
In a new study, they wanted to explore the effects of rocking on sleep and its associated brain waves throughout the night.
The researchers enlisted 18 healthy young adults to undergo sleep monitoring in the lab.
The first night was intended to get them used to sleeping there.
They then stayed two more nights - one sleeping on a gently rocking bed and the other sleeping on an identical bed that wasn't moving.
The data showed that participants fell asleep faster while rocking.
Once asleep, they also spent more time in non-rapid eye movement sleep, slept more deeply, and woke up less.
Next, the researchers wanted to know how that better sleep influenced memory.
To assess memory consolidation, participants studied word pairs.
The researchers then measured their accuracy in recalling those paired words in an evening session compared to the next morning when they woke up.
They found that people did better on the morning test when they were rocked during sleep.
"Having a good night's sleep means falling asleep rapidly and then staying asleep during the whole night," Bayer said.
"Our volunteers - even if they were all good sleepers - fell asleep more rapidly when rocked and had longer periods of deeper sleep associated with fewer arousals during the night.
"We thus show that rocking is good for sleep."
Meanwhile, another new study has found your genes may be responsible for whether you're a morning person.
A recent study used information based on wrist-worn activity trackers, worn by more than 85,000 individuals, that led to the discovery of some new genes associated with early risers.
Researchers found that the genetic areas impacted sleep timing, but not quality or duration.
It has highlighted how "night owls" were at a higher risk of mental health issues, including depression and schizophrenia.
Streaming chill vibes? This might be why
Here's another thing about night owls: they most likely prefer relaxing, low-intensity music.
In fact, what music we listen to is influenced by anything from time of day and season, to gender, age and geography.
A Cornell University study found people of every culture listen to more relaxing music late at night and more energetic music during daytime business hours.
The researchers also found that across cultures, people were more likely to listen to less intense music as they got older.
Their study covered some 765 million online music plays, streamed from Spotify in 2016, by around a million people from 51 countries.
The researchers used Spotify tools rating the musical intensity from "highly relaxing (acoustic, instrumental, ambient and flat or low tempo) to highly energetic (strong beat, danceable, loud and bouncy)."
Almost half of internet users between ages 16 and 64 stream music during the day.
The study found that people in the West tend to play more arousing music, while those in Asia play more relaxing music, consistent with other research reflecting a cultural preference for high-versus-low-arousal positive emotional states.
And while globally women listen to music with lower intensity, particularly in the evening, the researchers found a hemispheric gender difference.
In the Southern Hemisphere, women chose music with higher intensity than men; in the Northern Hemisphere, the pattern was the opposite.
A person's chronotype influenced music choice as well: "Night owls" streamed music of lower intensity, while "evening people" listen to music with the highest intensity scores.
However, the increase in intensity of night owls' choices for their daytime music choices was proportionately greater than the other chronotypes, which may reflect their use of musical stimulation to help them remain alert during the day, the researchers said.
Body image: why not caring is good
Spending time with people who aren't hung up about their bodies can improve your own eating habits and body image.
In a new study, Canadian researchers found there was a detrimental effect to being around people preoccupied with body image – and a positive one with interacting with people who weren't.
"Our research suggests that social context has a meaningful impact on how we feel about our bodies in general and on a given day," said Kathryn Miller, PhD candidate in clinical psychology at the University of Waterloo.
"Specifically, when others around us are not focused on their body it can be helpful to our own body image."
Miller and colleagues asked 92 female undergraduate students aged 17 to 25 to complete a daily diary over seven consecutive days and reflected on their interactions with "body focused" and "non-body focused" people.
The study measured participants' frequency of daily interactions, body satisfaction, and whether they ate according to hunger and cravings, rather than fixating on their dietary and weight goals.
It ultimately found that spending more time with non-body focused individuals may be advantageous in protecting against disordered eating and promoting more intuitive eating.
"If more women try to focus less on their weight and shape, there may be a ripple effect shifting societal norms for women's body image in a positive direction," Miller said.
"It's also important for women to know that they have an opportunity to positively impact those around them through how they relate to their own bodies."