Sleeping more than eight hours is associated with a notable increase in dying from heart disease including heart attacks.

Too much sleep is a troublemaker, says Beate Strand’s study that was conducted by Taiwanese and Norwegian researchers.

What does more than eight hours of sleep mean?
A 53 percent higher risk of death from heart disease (including heart attacks) when compared to study subjects who reported sleeping between six and eight hours. Now here’s what’s unnerving: Other risk factors for heart disease were adjusted for, but the risk still came in at 28 percent greater.

The following variables were adjusted for: age, BMI, sex, blood sugar, systolic blood pressure, smoking, drinking, blood lipids, diabetes, physical activity and past cardiovascular disease.

So if you’re thinking, “Maybe people who sleep longer than eight hours are more likely to smoke, overeat or never exercise,” well, this scenario goes down the tubes. However, the study participants’ lifestyle was self-reported, and we all know how subjective “physical activity” can be.

There are people who believe they get plenty of exercise, when in actuality, they’re sedentary and get no structured aerobic exercise or strength training workouts.

The effects of more than eight hours of sleep have not been studied on specifically people in great physical condition—a status that can be measured objectively (i.e., the ability to perform high levels of physical activity such as chin-ups, heavy deadlifts, overhead presses, hill dashing, land sprints, sustained running, plus other objective features such as low body fat percentage, low blood pressure (not just the absence of high blood pressure), etc.

The researchers cannot explain a cause and effect, only an association, between heart problems and sleeping over eight hours. Another mystery is that this association mainly applies to women.

Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.  
Source: Sleeping Over 8 Hours Bad for the Heart