Intermittent Fasting and Cardiovascular Health: Decoding the Facts
Aditi Shenai
March 4, 2025
Weight Loss
Intermittent fasting has gained immense popularity as a lifestyle choice for weight management and overall health. Many people believe it benefits cardiovascular health, thereby reducing the risk of heart disease, high blood pressure, and metabolic disorders.
A recent report by the American Heart Association (AHA) has raised concerns. The study claims that an 8-hour time-restricted eating window can lead to a 91% higher risk of cardiovascular death. This report leaves many questioning whether intermittent fasting is bad for the heart.
At the same time, numerous research studies support intermittent fasting for heart health. These reports suggest that fasting may lower blood pressure, reduce inflammation, and improve cholesterol levels. At the same time, it can enhance overall cardiovascular function. This conflicting information can create confusion, making it difficult to determine the true impact of fasting on heart health.
This article aims to decode the real effects of intermittent fasting on cardiovascular health. It will explore the details of the AHA study and provide science-backed insights on whether fasting is genuinely beneficial or harmful for the heart. Understanding the nuances, benefits, risks, and considerations can help individuals make informed decisions about intermittent fasting and heart health.
What is Intermittent Fasting?
Intermittent fasting (IF) is an eating pattern that alternates between periods of eating and fasting. It is not about what you eat but when you eat. The primary goal of intermittent fasting is to enhance metabolic flexibility. It aims to make the body use stored fat for energy when food intake is restricted.
There are several common types of intermittent fasting:
- 16:8 Method: Fasting for 16 hours and eating within an 8-hour window (e.g., eating from 12 PM to 8 PM and fasting overnight).
- 5:2 Diet: Eating normally for five days a week and restricting calories (500-600 kcal) for two non-consecutive days.
- Alternate-Day Fasting (ADF): Fasting every other day with little to no calorie intake on fasting days.
- 24-Hour Fasting (Eat-Stop-Eat): A full-day fast once or twice a week, consuming no food for 24 hours.
- One Meal a Day (OMAD): Eating one large meal per day and fasting for the remaining 23 hours.
Each method affects the body differently, particularly regarding blood sugar regulation, cholesterol levels, and cardiovascular function. However, recent debates have questioned whether time-restricted eating increases the risk of cardiovascular disease or if it offers heart-protective benefits.
A Research Associating Intermittent Fasting with Heart Attack
A controversial study presented at the American Heart Association’s 2024 EPI|Lifestyle Scientific Sessions claimed that time-restricted eating may increase the risk of cardiovascular death. The study analyzed 20,000 adults who participated in the National Health and Nutrition Examination Surveys (NHANES) between 2003 and 2018. Researchers tracked their dietary habits and cardiovascular outcomes over an 8-year period.
Key Findings from the Study:
- Participants who followed the 16:8 intermittent fasting method were 91% more likely to die from cardiovascular disease than those who did not follow time-restricted eating.
- Individuals with pre-existing cardiovascular conditions who ate all their meals within an 8-10 hour window had a 66% higher risk of dying from heart disease and stroke.
- No overall survival benefit was found for time-restricted eating when analyzing long-term heart health and mortality rates.
Limitations of the Study:
While the findings were concerning, experts have raised several questions and concerns regarding the study’s accuracy:
- Dietary Recall Issues: The study relied on self-reported dietary data collected twice at the time of enrollment. Since dietary habits change over time, this may not accurately reflect long-term eating patterns.
- Observational Nature: The research was observational, meaning it cannot establish direct causation between intermittent fasting and cardiovascular death.
- Confounding Factors: The study did not fully account for lifestyle differences, such as smoking, alcohol consumption, sleep quality, physical activity, and stress levels, which significantly impact heart health.
- Contradictory Findings: Prior research supports fasting as a heart-healthy practice, improving cholesterol levels, insulin sensitivity, and inflammation markers.
Intermittent Fasting for Heart Health: Are There Any Benefits?
Intermittent fasting (IF) has been widely recognized for its weight loss and metabolic benefits, but its connection to heart health is an ongoing subject of debate. While the recent study from the American Heart Association (AHA) suggests a higher cardiovascular risk, other scientific research highlights the potential heart-protective effects of intermittent fasting. Rather than directly improving heart health, fasting may support various metabolic functions that lower the risk of cardiovascular disease.
Below are some of the ways intermittent fasting may benefit heart health, backed by scientific logic and physiological mechanisms.
1. Supports Healthy Weight Loss
Obesity is a significant risk factor for heart disease, high blood pressure, and stroke. Intermittent fasting helps with caloric restriction and fat loss. It leads to a better body mass index (BMI). Research suggests that losing 5-10% of body weight significantly reduces the likelihood of hypertension, heart failure, and heart attacks.
A controlled study found that time-restricted eating leads to sustained weight loss and helps regulate hunger hormones like ghrelin, preventing overeating. With less visceral fat, the heart experiences less strain, improving cardiovascular efficiency.
2. Improves Insulin Sensitivity and Blood Sugar Control
High insulin resistance is a precursor to type 2 diabetes and heart disease. Studies indicate that intermittent fasting reduces fasting blood sugar levels by 3-6% and insulin resistance by 20-30%. Lower insulin levels mean reduced arterial inflammation and plaque buildup, which lowers the risk of atherosclerosis (hardening of the arteries).
By enhancing glucose metabolism, fasting may help prevent cardiovascular disease and improve overall metabolic health.
3. Reduces Inflammation and Oxidative Stress
Chronic inflammation contributes to heart disease, hypertension, and stroke. Intermittent fasting activates autophagy, a natural process where the body removes damaged cells and reduces oxidative stress.
According to research, fasting lowers pro-inflammatory markers like C-reactive protein (CRP) and interleukin-6, both of which are associated with cardiovascular disease risk.
4. Regulates Blood Pressure
One of the significant intermittent fasting cardiovascular benefits is its potential to lower blood pressure. During fasting, sympathetic nervous system activity decreases, reducing vascular resistance and strain on arteries.
A meta-analysis found that individuals following intermittent fasting experienced an average decrease of 3-5 mmHg in systolic blood pressure. This reduction can significantly lower the risk of hypertension-related heart disease.
5. Improves Cholesterol and Triglyceride Levels
High levels of LDL (bad cholesterol) and triglycerides contribute to atherosclerosis. That increases the risk of heart attacks and strokes. Intermittent fasting can reduce LDL cholesterol levels by 10-25% while raising HDL (good cholesterol).
A study found that fasting enhances fat metabolism. Hence, it prevents lipid accumulation in arteries and supports heart health.
While these benefits suggest a positive correlation between intermittent fasting and heart health, individual factors, dietary quality, and fasting duration play a significant role in determining long-term effects.
Intermittent Fasting for Heart Health: The Drawbacks
Despite its potential benefits, intermittent fasting is not risk-free, particularly for individuals with pre-existing heart conditions. Some of the reported downsides of fasting on cardiovascular health include:
1. Potential for Increased Stress Hormone Levels
Fasting increases cortisol (the stress hormone), which can elevate blood pressure and heart rate. If you do not manage fasting properly, prolonged stress responses may lead to chronic inflammation, which negatively affects cardiovascular function.
2. Risk of Nutrient Deficiencies
A poorly structured fasting diet may lack essential nutrients like potassium, magnesium, and omega-3 fatty acids, all of which are crucial for maintaining heart health. If fasting is combined with poor dietary choices, it may contribute to high cholesterol, hypertension, and metabolic imbalances.
3. May Worsen Existing Heart Conditions
People with heart disease, previous heart attacks, or high blood pressure need to approach fasting cautiously. Fasting can alter fluid balance, potentially causing dehydration and low blood pressure episodes, which may lead to fainting or dizziness.
While intermittent fasting does not directly cause heart disease, those with underlying heart conditions should consult a cardiologist before adopting a fasting routine.
Can Fasting Cause Heart Palpitations?
The connection between Intermittent Fasting and heart palpitations is one of the most debated ones. Heart palpitations are among the most common concerns related to intermittent fasting and heart health. While fasting itself does not directly cause heart problems, certain factors may trigger irregular heartbeats or increased heart rate during fasting periods.
1. Blood Sugar Fluctuations
Fasting lowers glucose availability, which can cause hypoglycemia (low blood sugar). When blood sugar drops too low, the body releases adrenaline. That can lead to heart palpitations during fasting.
2. Dehydration and Electrolyte Imbalance
Fasting can cause electrolyte imbalances, particularly low potassium, sodium, and magnesium levels, all of which are essential for heart function. Dehydration can lead to low blood volume, forcing the heart to pump harder and causing palpitations.
3. Increased Sympathetic Nervous System Activity
Fasting activates the sympathetic nervous system, which can increase heart rate fasting responses. People who experience anxiety, high caffeine intake, or chronic stress may notice heart palpitations when fasting due to heightened nervous system stimulation.
4. Existing Heart Conditions
Individuals with arrhythmias, mitral valve prolapse, or other cardiovascular disorders may experience worsened symptoms while fasting. In such cases, monitoring heart rate fasting fluctuations is essential.
If heart palpitations persist, adjusting hydration, electrolyte intake, or fasting duration may help manage symptoms. Consulting a healthcare provider is advised for those with persistent cardiac concerns.
Important Tips for Heart-Healthy Intermittent Fasting
To maximize the cardiovascular benefits of intermittent fasting while minimizing potential risks, consider these essential tips:
1. Choose a Balanced Eating Window
- Avoid overly restrictive time frames that lead to nutrient deficiencies.
- A 10-12 hour eating window may be safer for heart patients than extreme fasting.
2. Stay Hydrated
- Drink plenty of water to prevent dehydration and electrolyte imbalance.
- Include potassium-rich foods like bananas and spinach in meals.
3. Avoid Processed Foods
- Focus on a heart-healthy diet with lean proteins, whole grains, and healthy fats.
- Avoid trans fats and refined sugar, which may increase cardiovascular risk.
4. Monitor Heart Health
- Check blood pressure and heart rate fasting responses regularly.
- If you experience frequent heart palpitations while fasting, modify your diet or schedule.
5. Seek Professional Guidance
Before starting intermittent fasting for heart health, consult a cardiologist or registered dietitian.
For structured fasting plans, HealthifyMe’s Health AI Plans provide customized fasting schedules, meal tracking, and heart-friendly diet plans, making fasting safer and more effective.
HealthifyMe Note
Intermittent fasting has its pros and cons, especially when it comes to cardiovascular health. While research highlights potential benefits, such as lower blood pressure, improved cholesterol, and reduced inflammation, studies also raise concerns about its long-term impact on heart health. The truth is, there is no one-size-fits-all approach. The key lies in balance and personalization. If done without proper guidance, fasting can lead to nutrient deficiencies, heart palpitations, and even cardiovascular risks. However, structured fasting with expert supervision can help you reap the benefits while avoiding potential pitfalls. The key takeaway is that you should listen to your body, make informed decisions, and seek professional advice before adopting a fasting routine—especially if you have a history of heart disease, high blood pressure, or arrhythmias. Sustainability and a heart-healthy lifestyle should always take precedence over extreme fasting methods.
The Final Word
Intermittent fasting is a widely debated practice with both potential cardiovascular benefits and risks. While some studies highlight its positive effects on weight loss, blood sugar control, and cholesterol, concerns remain about how it impacts heart function in the long run. The recent study linking time-restricted eating to cardiovascular death has undoubtedly added a layer of caution. However, it is essential to look beyond headlines and consider individual health factors. Not all fasting methods work for everyone, and for those with pre-existing heart conditions, fasting should be approached with medical guidance.
So, is intermittent fasting right for you? The answer depends on your overall health, lifestyle, and goals. If your aim is fasting for heart health, it is essential to follow a sustainable plan, prioritize nutrient-rich meals, stay hydrated, and monitor your body’s response. Instead of extreme restrictions, adopting a balanced, heart-friendly approach to nutrition and fasting is the best way forward.
A very important factor to note is that choosing the right foods to consume while practicing intermittent fasting is imperative. If you follow this practice but indulge in high-calorie foods such as refined carbs, sweets, desserts, fried foods, etc., you will be unable to reap the actual benefits of this lifestyle. Also, this lifestyle needs to be adopted once you discuss your options with your medical practitioner and/or nutritionist.
HealthifyMe’s AI-driven Health Plans, such as HealthifyTrack+ with Intermittent Fasting, provide customized fasting schedules, meal tracking, and real-time insights. These plans ensure that your fasting journey supports your heart health rather than compromising it.
Frequently Asked Questions (FAQs)
Q: Does intermittent fasting cause heart disease?
A: There is no definitive proof that intermittent fasting directly causes heart disease. However, studies indicate that prolonged fasting without proper nutrition may contribute to high-stress levels, nutrient deficiencies, and electrolyte imbalances, all of which can increase the risk of cardiovascular issues.
Q: Can intermittent fasting cause high blood pressure?
A: Intermittent fasting can either lower or raise blood pressure, depending on how you implement it. Fasting may reduce hypertension by improving insulin sensitivity and reducing body weight. However, prolonged fasting, dehydration, or excessive stress can lead to elevated cortisol levels, which may contribute to higher blood pressure.
Q: Why do I experience heart palpitations while fasting?
A: Heart palpitations during fasting can occur due to low blood sugar levels, dehydration, or electrolyte imbalances. When fasting, the body adjusts to using stored fat for energy, which can sometimes cause fluctuations in heart rate. If you experience frequent palpitations, ensure you are drinking enough fluids, consuming enough minerals (sodium, potassium, magnesium), and breaking your fast with a balanced meal. If symptoms persist, consult a doctor.
Q: Is intermittent fasting bad for your heart?
A: Intermittent fasting is not necessarily harmful to heart health, but it depends on individual health conditions and how you practice fasting. While it may help reduce heart disease risk factors, such as obesity and high cholesterol, fasting without proper nutrition can lead to muscle loss, fatigue, and cardiovascular stress.
Q: Can fasting lower blood pressure?
A: Yes, fasting can help lower blood pressure by reducing sodium intake, improving insulin sensitivity, and promoting weight loss. However, extreme fasting or prolonged dehydration may lead to dizziness, electrolyte imbalances, and irregular heart rhythms, which can negatively impact blood pressure regulation.A: Yes, fasting can help lower blood pressure by reducing sodium intake, improving insulin sensitivity, and promoting weight loss. However, extreme fasting or prolonged dehydration may lead to dizziness, electrolyte imbalances, and irregular heart rhythms, which can negatively impact blood pressure regulation.
Q: Can fasting cause heart attacks or heart failure?
A: There is no conclusive evidence that fasting directly causes heart attacks or heart failure. However, individuals with pre-existing heart conditions should be cautious. Extreme fasting or inadequate nutrient intake may increase stress on the cardiovascular system, leading to heart rhythm abnormalities or worsening existing heart conditions. Those at high cardiovascular risk should consult a doctor before attempting intermittent fasting.
Q: How can I safely practice intermittent fasting for heart health?
A: To safely practice intermittent fasting without increasing cardiovascular risk, focus on moderation, hydration, and nutrient balance. Avoid extreme fasting methods, eat a balanced diet rich in heart-friendly foods (fruits, vegetables, whole grains, lean proteins, and healthy fats), and stay active. Using structured fasting plans like HealthifyTrack+ with Intermittent Fasting can help you track calories, optimize fasting schedules, and maintain overall heart health.
Research Sources
1. 8-hour time-restricted eating linked to a 91% higher risk of cardiovascular death
2. The Effect of Fasting on Cardiovascular Diseases: A Systematic Review
3. Effects on cardiovascular risk factors of weight loss limited to 5–10 %
7. The Role of Intermittent Fasting on Metabolic Syndrome: A Systematic Review and Meta-Analysis
9. The Effect of Fasting on Human Metabolism and Psychological Health
