We’ve covered the topic of diet and cholesterol several times - dietary cholesterol doesn’t have a huge effect on blood cholesterol, and there’s very little evidence that eating whole foods rich in cholesterol (e.g., eggs, meat, butter) raises blood cholesterol in most people. Even the latest version of the Dietary Guidelines finally had to admit that there’s no real scientific evidence for strict cholesterol limits in most people.
But blood cholesterol is still something a lot of people want to keep an eye on. Sure, it’s not as simple as butter causing heart attacks, but the way we choose to live does have an effect on blood cholesterol, and it isn’t limited to food at all.
As a quick review: blood cholesterol is more complicated than “higher number = bad.” Here’s a quick review for anyone who needs one - now take a look at 3 lifestyle factors that can affect blood cholesterol totally independent of diet.
The short version: sleep deprivation is awful for you in almost every imaginable way, and throwing blood cholesterol way out of whack is unfortunately one of those ways.
Sleep deprivation reduces blood levels of HDL cholesterol and elevates LDL cholesterol, as well as affecting inflammatory pathways that increase cardiovascular risk. This is measurable in children as young as 12, which is a scary thought when you think about how much time some 12-year-olds spend on their phones late at night.
Social jetlag (that’s when your body’s sleep schedule is mis-aligned with your work or social schedule) is associated with cholesterol issues. So the natural night owls who have to get up at 6 for an 8am shift are at risk there, and so are the weekend party animals who sleep from 2am to noon on Friday and Saturday, only to abruptly shift back to a “normal” schedule during the week. And it’s not just staying up too late that can do it: patients with sleep apnea (a sleep disorder that reduces sleep quality) also have higher levels of LDL cholesterol.
Short or fragmented sleep is also associated with the development of plaque in the arteries - which is actually the reason why anyone cares about cholesterol in the first place. In one study of adults in Nevada, people with “deficient sleep” (1-4 hours every night) were 2.5 times as likely to have cardiovascular disease than people with normal sleep (7-8 hours).
In conclusion: go to bed! Your arteries will thank you!
2. Sitting time
Another culprit for cholesterol problems is just sitting all day.
In one review and meta-analysis, sedentary time was associated with higher triglycerides and lower HDL. Other studies have concluded differently, but at least some research has concluded that sedentary time increases cardiovascular risk and is associated with higher LDL/lower HDL independently of exercise time.
In other words, if you currently sit in a chair for 14 hours every day, the answer is not to get up and spend half an hour every day powering through a violently brutal high-intensity workout and then continue sitting for the other 13.5 hours. This research actually suggests that it would be better to break up total sedentary time - maybe with a standing desk, long walks, stretch breaks, an active commute (walking or biking), or some other form of regular, gentle activity that reduces sitting time.
Moderate or strenuous physical activity does also help - cardiovascular fitness and regular exercise both reduce LDL cholesterol. So in principle, not being sedentary is good, and adding workouts to that is even better. But hold that thought for a minute because first it’s time to talk about...
It shouldn’t really be a shock that stress is bad news for blood cholesterol, considering what bad news it is for everything from weight loss to mental health. But there’s actually been research on this, showing that psychological stress is dangerous for blood lipid levels and cardiovascular health generally - chronic stress in particular seems to change blood cholesterol levels in all the wrong directions.
Interestingly, one paper found psychological hardiness predicts whether people’s cholesterol levels will change in negative ways when they’re exposed to stress. The researchers defined “hardiness” as “commitment, tendency to regard life as interesting and meaningful; control, belief that one can influence outcomes by taking action; and challenge, an adventurous, exploring approach to living.” In other words, the same stressful event might have very different effects on different people's cholesterol levels, depending on how they react.
A problem you can sweat your way out of?
Speaking of stress, and getting back to that point about the exercise, this study is really interesting. The researchers wanted to understand the relationship between stress and cholesterol, and how it might depend on physical fitness. They found that people with higher life stress had higher LDL cholesterol levels and an overall worse lipid profile, just as they had expected. But people who had high life stress and high cardiovascular fitness were a lot better off than people with high life stress and low cardiovascular fitness.
In other words, cardiovascular fitness may help reduce some of the effects of chronic stress. Physical work (e.g., working as a dog walker instead of an administrative assistant) also seems to protect people from the effects of chronic stress on blood lipids.
In short: don’t stress the egg yolks, but do go for a walk.
For the sake of sanity, it's important to remember that nobody can completely control their own blood cholesterol levels. There’s always an element of genetics, plus the role of sheer good or bad luck. On a population level, sure, people in general would be healthier if they slept more, stressed less, and spent less time sitting. But even in an imaginary society where everyone did everything right, there would probably still be people with high cholesterol because nobody’s health is completely under their control.
But with that said, all of these studies do suggest that the “big three” lifestyle factors - sleep, stress, and sedentary time - have a lot to do with any individual’s blood lipids and general cardiovascular health. In practical terms, that means:
- Get enough sleep.
- Learn strategies for managing and coping with stress
- Sit as little as possible, and build up your cardiovascular fitness - especially if you’re stressed.
...most of which is good advice regardless, for just about anything that might ail you! Have you ever tried any kind of lifestyle change to address cholesterol levels? What was it? How did it go? Let us know on Facebook or Twitter!