Intermittent fasting has become a popular approach to eating, with many people trying it to support weight loss and improve energy levels. But does it have any effect on heart health? Here, we answer your questions.
What is intermittent fasting?
Intermittent fasting isn’t about what you eat, but when you eat. It involves blocking out periods of the day to eat and periods to fast, and it can work in various combinations.
Some decide to eat during an 8-hour window each day and fast for the remaining 16 hours. Others may choose to eat normally for five days of the week and restrict calories on the other two days.
The main idea is to give your body longer breaks between eating. During fasting periods, your body shifts from using glucose as its main fuel source to burning stored fat instead. This change can help with weight loss, and several popular fasting methods exist.
Popular ways of intermittently fasting:
There’s no definitive way to try intermittent fasting, but these are the most common:
- 16:8 method – This time-restricted approach means you should eat all your meals for the day within an 8-hour window, such as between 10am and 6pm, then fast for the remaining 16 hours.
- 5:2 diet – Eat as you normally would for five days of the week, but reduce calories to around 500–600 on two non-consecutive days.
- Alternate-day fasting – Switch between one day of normal eating and one day of fasting, which you repeat throughout the week.
- Eat-Stop-Eat – Involves a full 24-hour fast of no eating at all once or twice a week, with regular eating on the other days.
The effects of fasting on the heart
Intermittent fasting can also affect some key risk factors linked to heart health. So what impact does fasting have on blood pressure, cholesterol and the long-term risks of cardiovascular disease? Let’s break it down across these different areas.
Does fasting lower blood pressure?
Some studies suggest intermittent fasting can help lower blood pressure, particularly in people with high readings. Fasting gives the body a rest from constant digestion and the insulin spikes that occur when we eat regularly, potentially reducing strain on blood vessels.
Lower blood pressure means less stress on the heart, lowering the chances of a heart attack, stroke or kidney failure.
Can fasting reduce cholesterol levels?
Research shows intermittent fasting may help reduce bad cholesterol and triglycerides (a type of fat found in the blood that, in high levels, can raise the risk of heart disease) while supporting higher levels of good cholesterol. This balance is important as it helps keep arteries healthy.
How does fasting affect heart disease risk?
Fasting can indirectly reduce the overall risk of heart disease by improving blood pressure and cholesterol. Some studies also show that fasting might lower inflammation, another factor contributing to heart and artery damage.
It’s worth noting that the results aren’t the same for everyone, and lifestyle factors, like diet, exercise and smoking habits, continue to play a huge role in fighting heart disease. Therefore, fasting alone is unlikely to reduce the risk of heart disease entirely.
Intermittent fasting and cardiovascular disease
Cardiovascular disease is a broad term that includes heart disease, stroke and problems with blood vessels. While early research is promising, intermittent fasting isn’t a guaranteed way to prevent these conditions. It may help reduce certain risk factors but should be considered part of a bigger picture plan.
Eating balanced meals, staying active, and keeping up with medical check-ups are all just as important for detecting and preventing cardiovascular disease.
Safety considerations
Intermittent fasting has many potential benefits, but it isn’t suitable for everyone. If you have an existing heart condition or other health concerns, it’s important to understand the possible risks before changing your typical eating routine or introducing new habits.
Is fasting safe for heart patients?
Some people with heart disease may benefit from fasting, especially if it helps with weight loss, blood pressure, or cholesterol management. However, fasting can affect blood sugar levels and overall energy levels.
Fasting can also interfere with medications you’re taking. If you’re taking medication for high blood pressure, diabetes or cholesterol, then long fasting periods may interfere with how those drugs work in your body.
That’s why anyone with a heart condition should only try intermittent fasting under medical supervision. Your doctor can help adapt the approach to find what works for you – or advise against it if it could ultimately do more harm than good.
Dangers of intermittent fasting
Fasting isn’t risk-free, even for people without diagnosed heart problems. Some common side effects include:
- Headaches, dizziness or fatigue – especially in the early stages
- Irritability or difficulty concentrating during fasting hours
- Risk of overeating during eating windows, which can cancel out benefits
- Possible nutrient deficiencies if meals aren’t balanced
When to seek medical advice
You should speak to a healthcare professional before trying intermittent fasting if you:
- Have heart disease or a history of cardiovascular problems
- Take regular medication for blood pressure, diabetes or cholesterol
- Are pregnant or breastfeeding
- Are underweight
- Have a history of eating disorders
Even if you’re generally healthy, you should check in with your doctor if you notice unusual symptoms. These might include chest pain, extreme fatigue, dizziness or fainting while fasting.
Overview
- Intermittent fasting changes when you eat, and not usually what you eat
- It may support heart health by lowering blood pressure, improving cholesterol balance and reducing inflammation
- Fasting isn’t risk-free – some people experience side effects, and strict patterns (like an 8-hour eating window) may even carry risks
- People with heart conditions, on medication or with other underlying health concerns should seek medical advice before trying it
Sources
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