Elon Musk has made two bold claims to his 100 million+ Twitter followers about how we can improve our quality of sleep.
"For improved quality of sleep, raise head of your bed by about 3” or 5cm and don’t eat 3 hours before bedtime," the CEO of Tesla, 51, wrote.
While many questioned the legitimacy of his recommendations and pointed people in the direction of healthcare professionals instead for advice, others wanted to understand what the proposed benefits were.
"Anyone want to explain why these two things help to me," YouTuber Jimmy Donaldson, better known as MrBeast, asked.
"Good chance you’re experiencing at least mild acid reflux at night, affecting quality [of] sleep without consciousness awareness," replied Musk.
So, what do Musk's sleep claims mean and how valid are they? Sleep therapist Tracy Hannigan, aka 'Tracy The Sleep Coach', talks us through them.
It seems the first claim might benefit some people, but hinder others. "Raising the head of your bed can be helpful for some people with reflux [when stomach acid travels up towards the throat] and some sleep disorders such as obstructive sleep apnoea," she says.
"Reflux can be a 'silent' cause of nighttime waking in some people."
Some people with asthma can also benefit from being propped up in bed. "Lying on your back puts extra pressure on your chest and lungs. This makes it harder to breathe," explains the Asthma + Lung Uk website.
"It can also trigger a cough because mucus in your nose can drip to the back of your throat. If you get acid reflux lying flat might make it worse, and the acid can irritate your airways. Propping yourself up with pillows can help to keep your airways open."
While there can be benefits for some, Hannigan adds, however, "Any persistent nighttime waking should be assessed as there are other common causes that would be approached in other ways – and additionally, raising the head of the bed might not be safe for some people."
And Musk's second claim isn't quite so absolute either. "It is generally not recommended to eat a large meal, particularly spicy ones, close to bedtime to help avoid reflux and other digestive problems," she says, before adding, "it isn't a hard and fast rule, however".
This is because "people shouldn't go to bed hungry to avoid waking due to hunger and running out of glycogen/fuel, and some people need a snack at bedtime to avoid this happening".
"Anyone with a medical or health issue should always speak to their doctor before setting windows where they will not eat as it might not be safe for them," Hannigan urges.
And what exactly does Musk mean by we might be experiencing "at least mild acid reflect at night" which "affects quality of sleep without consciousness awareness"?
Hannigan explains that reflux symptoms can be worsened by laying flat, and so mild acid reflux which may go unnoticed during the day, could possibly create some symptoms in the night.
"If they are very mild we might not notice these, and they could promote nighttime wakings that we are unaware of unless we wake and notice the symptoms, she explains.
But she adds, "Mild reflux is one possible cause out of many possible causes for nighttime wakings and disturbed sleep, and we can't assume all night waking and poor quality sleep is related to reflux."
Other common causes of poor sleep quality (like sleep apnoea and other sleep disorders) have more significant health consequences than very mild reflux. "Any poor sleep quality complaint should always be fully assessed so that appropriate interventions can be delivered," urges Hannigan.
Watch: How to get more sleep
So, what are Hannigan's main recommendations for improving sleep quality?
"Sleep drive is responsible for overall sleep quality," she says. "Increasing sleep drive by consistently waking at the same time of day, being physically active, and staying up until one is very sleepy is the best way for most people to get better, deeper and more refreshing sleep."
If poor sleep is affecting your daily life, causing you distress or you're concerned about anything, call NHS 111 or talk to your GP, and consult a doctor before making changes to your sleep routine.