Exercise may not completely undo the effects of a poor diet, but it can certainly help. From giving your energy levels a boost to lowering your risk of heart disease and type two diabetes, the benefits of moving your body go far beyond maintaining or building your level of fitness.

Exercise can also be hugely beneficial for people with high cholesterol, although not always in the way you might expect. While working out can help to rid the body of LDL (bad) cholesterol, it can also lead to an increase in HDL (good) cholesterol. This is positive news. But why does that happen, and does it really matter? And how can we harness the power of exercise to keep our cholesterol levels under control? We asked the experts to explain all. 

Cholesterol is a type of fat found both in food sources and produced by the body. Most of the cholesterol in our bodies is produced in the liver, and from there it travels through the blood vessels in particles known as lipoproteins.

There are two main types of these lipoproteins: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). The latter of these cholesterol types is considered to be ‘good’ cholesterol because it carries cholesterol away from the cells and back to the liver, where it is removed. However, LDL cholesterol can build up on the blood vessel walls and cause health issues down the line, which is why it’s considered ‘bad’ cholesterol.

That’s not to say you want to get rid of your LDL cholesterol altogether – we need some LDL cholesterol in the blood to function – but having too high readings can lead to this build-up, which in turn can cause issues. 

If you’ve ever had a consultation with a doctor after a blood test that showed elevated LDL levels, it’s likely they suggested incorporating more exercise into your routine. Alongside reducing your intake of saturated fat, which can make it harder for the liver to reabsorb LDL cholesterol and lead to the production of bigger LDL molecules, exercise has been proven to reduce the amount of LDL cholesterol in the blood over time.

While experts don’t fully understand all the ways in which exercise can affect the levels of cholesterol in the blood, one of the main ways it helps is by encouraging the muscles to use triglycerides – a form of fat contained within LDL molecules – as a form of energy. “This can encourage the removal of excess triglycerides from the blood into the muscles, reducing LDL levels as a result,” explains Mhairi Keil, a nutritionist at Marylebone Health.

The HDL cholesterol increase that exercise can trigger (more on that later) can also help to reduce LDL cholesterol levels, thanks to a process known as ‘reverse cholesterol transport’.

“The ‘good’ cholesterol helps to transport the lower density type from the arteries back to be metabolised by the liver,” adds Dr Rebecca Robinson, a consultant in sports and exercise medicine at Marylebone Health. “It also has its own anti-inflammatory and antioxidant effect and can help to prevent blood clots.”  

The science behind why exercise boosts HDL cholesterol levels is complex, but there are two main ways it helps to boost our good cholesterol: by increasing levels of lipoprotein lipase (LPL) and reducing levels of cholesterol ester transfer protein (CETP). While the former helps to produce new HDL molecules, the latter stops the components found in HDL from being transferred to other forms of lipoprotein, like LDL.

As a result, you might find that your total cholesterol readings don’t dip massively when you start working out regularly – just your ratio of LDL to HDL. Indeed, one piece of analysis looking at the impact of 12 weeks or more of aerobic exercise on cholesterol levels found that, while HDL cholesterol increased by 4.6% and LDL cholesterol fell by 5%, total cholesterol remained relatively unchanged.  

The amount of exercise you need to do to support your overall health and cholesterol levels will depend on your body, but meeting the NHS’ physical activity guidelines is a good place to start.

“Evidence shows that 150 minutes of physical activity a week is beneficial to health, but up to 300 minutes (five hours) can have a more beneficial impact on cholesterol levels,” Dr Robinson explains. “Doing what’s achievable and sustainable for you is the most important factor.”

Alongside aerobic activity, Dr Robinson recommends adding in some form of resistance work – like weight training, pilates or yoga – to support your metabolism, which can impact cholesterol. “If you have not been regularly active for a while, just small amounts of exercise will have a big impact on your body metabolism, including cholesterol,” she says.  

It’s worth noting that there is an upper limit to the benefits exercise can offer for cholesterol levels. In fact, overexercising can have the opposite effect. “People who exercise in excess of what their body can adapt to, or those who have too low nutritional energy intake (relative energy deficiency in sport, or REDs) can slow down their bodies’ processes and raise cholesterol as a result,” Dr Robinson adds. “If this is the case for you, it’s a good idea to seek medical attention or see a dietitian as this is reversible.” 

Reducing your cholesterol levels takes time, so you shouldn’t book in for another blood test after just one week of working out regularly.

“It can take three to six months to see a change in your blood test results, but the changes will start on a cellular level within your body almost immediately,” Dr Robinson says. “If you’ve had a cholesterol reading, wait three or four months until a repeat.”

It’s important to remember that some people find it harder than others to decrease their cholesterol levels. “Some people will have a high level of lower density cholesterol, and possibly overall cholesterol than others for hereditary reasons,” Dr Robinson adds. “That means you can be ticking all the boxes for health and still see that your levels are high.”

If you’re struggling to get your cholesterol levels down despite exercising regularly and eating a good quality diet that’s low in saturated fat and high in fibre, it’s worth speaking to your GP to see what your options are. They may be able to prescribe medication to help. 

Images: Getty