Getting the recommended seven to eight hours of sleep a night is “super healthy”, said Dr Eric Berg.
But the expert, who has more than 11.2 million subscribers on YouTube, said there can be big implications to not getting enough rest, including risk of cardiovascular problems.
Posting to his channel, Dr Berg explained why we need rest in the first place: “That’s when our bodies recover, that’s when we burn the most fat, that’s when our bodies do the most detoxification, that’s when our brains detox, and this is why when you don’t get enough sleep, you’e going to feel toxic, especially in your head.”
While not getting enough sleep can cause fatigue and significant mood changes, it could also put you at risk of cardiovascular problems like stroke and diabetes.
Dr Berg explained when you don’t get enough sleep, sympathetic hyperactivity occurs.
He said: “It’s part of the nervous system called the sympathetic nervous system, and that system is in overdrive when you’re not sleeping, so you’re going to have more adrenaline, you’re going to have more cortisol because your adrenals are revved up.
“It is true that having an overactive, sympathetic nervous system can keep you up, but also not getting enough sleep can cause the adrenals and the stress and the sympathetics to kick in.
“The sympathetic nervous system is the accelerator of the nervous system and you’re not going to be able to sleep if it’s accelerated.”
This sympathetic overdrive, said Dr Berg, particularly if it’s chronic, puts stress on the heart.
Dr Berg continued: “You’re going to be at risk for cardiovascular problems – at risk for a stroke, at risk for being a diabetic – because cortisol and adrenaline releases sugar, which then increases insulin. Despite not eating any sugar, your sugar levels will be higher.
“Even the name of the adrenal hormones – another name for cortisol is glucocorticoids because it regulates glucose. So this is why you have impairments with glucose and problems with your blood sugars, insulin, which then leads to weight gain and a fatty liver.”
If you can’t sleep, you’re getting less than five hours, and you have sympathetic overdrive and you’re trying to lose weight, “good luck”, said Dr Berg, “it’s not going to happen”.
He added: “In fact, you can work with someone on their diet, but if their sleep is not right, and they’re also exercising at the same time, you’re wasting your time.”
He concluded, getting enough sleep results in huge changes in weight loss.