Review on the effects of fasting on cardiac patients

Abstract

Fasting in Ramadan involves the cessation of food, water, and other behaviors from dawn to sunset, creating a unique physiological stressor that might have a potentially injurious or beneficial effect on cardiac patients. Its impact should be known so as to optimize patient care. The aim of this paper is to review the literature relating to the effects of Ramadan fasting on cardiac health, with particular regard to high-risk patient management, medication adherence, and life-style modifications. Available data suggests that fasting in Ramadan is safe for stable cardiac patients, with improvements in BMI, lipid profiles, blood pressure, and others. However, high-risk groups, including patients with recent myocardial infarction or severe heart failure, were considered inappropriate for fasting. Additionally, medication adjustments and lifestyle changes regarding balanced diets and hydration strategies are necessary to make fasting safe in cardiac patients who are candidate for fasting patients. These findings support the need for future tailored fasting plans and evidence-based guidelines to optimize outcomes in cardiac patients.

1. Introduction

Fasting in the holy month of Ramadan is one of the basic tenets of Islam, entailing abstention from food, water, and certain behaviors throughout the time between dawn and sunset. Depending on the region, this sometimes may be as long as 16 consecutive hours. This is followed afterwards by feasting in the evening, known as Iftar. This act of devotion has immense impacts on lifestyle, dietary habits, and daily routine, which may drastically weigh on physiological processes. In cardiac patients, such alterations from fasting to feasting bring about unique problems that need evidence-based recommendations to minimize the potential risks that might be associated with it, while at the same time, ensuring adherence to religious requirements.

Some studies have shown that intermittent fasting results in favorable metabolic adaptations-for example, improvement in the lipid profile and insulin sensitivity-which have cardiovascular protective effects [1,2]. However, it is the prolonged periods of fasting and abrupt changes of mealtimes that might precipitate the underlying conditions in some patients with some predisposed cardiac conditions such as coronary artery disease (CAD) or heart failure, carrying potential risks like dehydration, electrolyte disturbances, and altered pharmacokinetics [3].

Moreover, it is important to address the psychosocial aspects of fasting with recognition of fasting as a soul and emotional nourishment requirement for Muslim patients. High risk patients are excused from fasting as per the instructions of Qura'n -the holy book of Islamic religion- however, many patients insist to fast Ramadan as volunteers for their own souls without religious obligations. There is actually a need, therefore, for sensitive counseling. Certain studies have analyzed that fasting facilitates community feeling, religious satisfaction, psychological well-being, all of these factors are opposed to clinical risks developed during fasting [4].

This review outlines the current evidence related to Ramadan fasting's outcomes in cardiac patients. It also emphasizes the need for individualized assessments to allow stratification by risk for cardiac patients in order to fast safely. This was reflected in other generic studies which classify these patients into categories of low, moderate, and high risk [3], and further provide health professional practical recommendations.

2. Literature search strategy

The databases involved in this review included PubMed, Embase, Google Scholar, and the Cochrane Library. The literature search was conducted through a structured iterative approach using a combination of primary keywords combined with Boolean operators. Core search terms included “fasting”, “religious observance”, “Ramadan”, “cardiac patient”, “heart disease”, “cardiovascular disease”, “Cardiachealth”. Filters were applied to certain databases to further narrow the results down to peer-reviewed articles, clinical trials, and expert reviews published in English. To make the search as comprehensive as possible, the search was conducted iteratively over 6 weeks from March–April 2025, with updates to allow for recently published studies. Citation chaining was also used, where references of selected articles were checked for other relevant studies. 33 articles in total were chosen (13 cohort) and (20 systematic reviews / meta-analyses / guidelines / reviews).

2.1. Cardiovascular health outcomes of Ramadan fasting in stable cardiac patients

The physiological effects of fasting on the heart are complex and multifaceted and may have opposite effects on stable cardiac patients. Indeed, evidence shows that fasting improves lipid profiles in terms of reduction in body mass index (BMI), waist circumference, low density lipoprotein (LDL), triglycerides, and improvement in high density lipoprotein (HDL) and overall metabolic parameters and immune system [[5], [6], [7], [8]]. However, lipid profiles in diabetic patients worsened with fasting, which was likely attributed to change in diet and anti-diabetic drug modifications, thus, requiring close monitoring [9]. Moreover, other studies investigated the effect of fasting on the incidence of cardiac events and hospitalizations. They reflected no significantly increased risk of cardiac events, stroke admissions, and hospitalizations in stable cardiac patients [9,10], neutral effect in diabetic patients [11], and a protective effect against hospitalization's severity in patients with acute heart failure [12]. However, there was an increased hospitalization risk in those with unstable angina, recent myocardial infarction, uncontrolled hypertension, decompensated heart failure, recent cardiac intervention or cardiac surgery [13]. Indeed, in a prospective study by Al Suwaidi et.al, fasting's effect was studied on 465 stable patients of various cardiac diseases including those with congestive heart failure, angina, atrial fibrillation, prior MI or coronary artery bypass surgery (CABG) and others. It was shown that while 91.6 % could fast, only 6.7 % felt worse with fasting [14]. Lastly, Hammoud et.al, demonstrated no adverse effects of fasting on blood pressure with improved heart rate variability (HRV) [15]. On the other hand, in high-risk patients, fasting may exacerbate symptoms or trigger acute events, and thus, those should not implement fasting at any cost, knowing that they are allowed religiously not to fast [16]. In conclusion, it is seemingly safe to say that Ramadan fasting is safe for patients with stable cardiac conditions, this includes patients with pre-existing well controlled heart condition with no exacerbation before Ramadan. Additionally, fasting may hold favorable outcomes in terms of improvement in BMI, lipid profile, and hospitalization severity. Table 1 summarizes the cardiovascular health outcomes of Ramadan fasting.

Table 1.

Impact of fasting on cardiac patients.

Study reference	Key outcome measures	Findings
Mazidi et al. (2015) [5]	Incidence of cardiovascular events during Ramadan, cardiometabolic risk profile changes.	Fasting showed no increase in acute cardiac illness during Ramadan. Improved lipid profiles (increased HDL, reduced LDL and total cholesterol), reduced weight, body fat, and BMI. However, lipid profiles of diabetic patients deteriorated, and long-term cardiovascular impacts remain unclear.
Nematy et al. (2012) [6]	Impact of Ramadan fasting on cardiovascular risk factors and 10-year coronary heart disease risk score.	Fasting led to significant improvements in the 10-year coronary heart disease risk score, HDL, cholesterol, triglycerides, LDL, systolic blood pressure, BMI, and waist circumference, but no significant changes in fasting blood sugar, insulin resistance, or hs-CRP.
Rouhani et al. (2014) [7]	Impact of Ramadan fasting on weight, lipid profile, diabetes management, immune system.	Weight decreased during Ramadan, lipid profiles improved (cholesterol and triglycerides in men, HDL in women), and fasting positively impacted the immune system.
Zare et al. (2021) [8]	Lipid profile	Significant improvements in LDL, HDL, and triglycerides levels during Ramadan fasting.
Salim et al. (2013) [9]	Cardiovascular events, hospitalization, Lipid profile	Stable cardiac patients showed no significant increase in hospitalizations. Lipid profiles in diabetic patients worsened, requiring close monitoring.
El Mitwalli et al. (2009) [10]	Stroke admissions	Ramadan fasting has no effects on stroke frequency, type, and severity. The duration of fasting has no effect on either frequency or type of stroke.
Almulhem et al. (2020) [11]	Cardiovascular outcomes in Type 2 diabetes patients	No conclusive evidence linking Ramadan fasting with increased or reduced cardiovascular events in people with diabetes.
Salam et al. (2018) [12]	Impact of Ramadan fasting on acute heart failure (AHF) hospitalizations, symptoms, management, and outcomes.	Patients hospitalized during Ramadan had lower prevalence of volume overload symptoms, less frequent atrial arrhythmias, and reduced cholesterol levels. Fasting had no adverse effects on immediate or 1-year mortality outcomes.
Chamsi-Pasha et al. (2016) [13]	Fasting impact on various cardiac disorders	Patients with unstable angina, recent myocardial infarction, uncontrolled hypertension, decompensated heart failure, recent cardiac intervention or cardiac surgery should avoid fasting because of increased hospitalization risk
Al Suwaidi et al. (2004) [14]	Comfort and incidence of cardiac events in patients with established cardiac diseases	91.2 % could fast, 6.7 % felt worsening of their symptoms with fasting
Hammoud et al. (2021) [15]	Cardiovascular health, heart rate variability (HRV), blood pressure in hypertensive patients during Ramadan.	No adverse effects on blood pressure; HRV improved, reduced cardiac stress.

2.2. High-risk patient identification

For appropriate risk stratification, counseling, and management, patients who might be at high risk from complications of fasting need to be identified. Multiple studies have tried to identify such patients, the most important to be tackled are as follows. First, patients with unstable angina, or history of myocardial infarction (MI). However, it was shown that fasting patients of this category were less likely to be hospitalized for heart failure or arrhythmia triggered by fasting [17]. Similarly, Ramadan fasting had insignificant effect on the occurrence of acute coronary syndrome (ACS) events in those with established ACS diagnosis [18]. Yet, it is advised not to fast within the first few weeks post MI, since there was an increased risk of cardiac events within 3 months of percutaneous coronary intervention in fasting patients [19]. Moreover, fasting patients with chronic coronary syndrome had no significant changes in dyspnea and chest pain compared to the non-fasting group as reported by Mousavi et al., where it was also recommended that patients with CAD and normal ejection fraction could fast, provided they do frequent check-ups [20]. Second, are patients with established heart failure. Interestingly, a systematic review conducted by Refaat et al. demonstrated that fasting didn't have an increased risk of decompensation and hospitalization in stable cardiac patients with heart failure [16]. However, those with advanced heart failure (Left ventricular ejection fraction ≤35 %, with class III–IV NYHA symptoms, or ≥ 1 hospitalization in the last 6 months due to decompensated heart failure, or those with severely impaired functional capacity) are considered very high risk, and must not fast [3]. Third, those with uncontrolled arrhythmias. Whereby, fasting was shown to increase the risk of arrhythmias and ischemic events, and patients were directed to avoid fasting [21]. Last, those with hypertension, since fasting might provoke blood pressure fluctuations. However, a review by Soleimani et al. has shown that fasting resulted in reduction in systolic, but not diastolic blood pressure, in most of the published articles. Still, fasting is only allowed under close medical supervision [22]. In summary, such findings emphasize that high risk patients require detailed pre-Ramadan assessments for the safety of fasting. This includes clinical stability, recent cardiac events, and medication requirements. Accordingly, patients with controlled symptoms may safely fast. Table 2 summarizes the probable high-risk cardiac patient categories for Ramadan fasting.

Table 2.

Characteristics of high-risk cardiac patients during Ramadan fasting.

Study reference	Risk group	Observations	Recommendations
Refaat et al. (2024) [16]	Heart failure	No significantly increased risk of decompensation and hospitalization with fasting	Precautions needed, prioritize medical stabilization.
Salam et al. (2013) [17]	ACS and or/ history of MI	Less likely to be hospitalized for heart failure or arrhythmia with fasting	No fasting within 6 weeks post-MI
Raffee et al. (2020) [18]	ACS + fasting	Insignificant effect of Ramadan fasting on ACS events	Patients with CAD and normal ejection fraction could fast, provided they do frequent check-ups.
Mousavi et al. (2014) [20]	Chronic coronary syndrome + fasting	No significant change in dyspnea and chest pain between fasting and non-fasting group	Patients with CAD and normal ejection fraction could fast, provided they do frequent check-ups.
Kahraman et al. (2020) [21]	Uncontrolled ventricular arrhythmias	High risk of arrhythmias and ischemia during fasting	Avoid fasting; regular monitoring required.
Soleimani et al. (2016) [22]	Hypertension	Most studies show reduction in systolic but not diastolic blood pressure in fasting patient	Fasting only under close medical supervision.

2.3. Medication adherence and adjustments

During the holy month of Ramadan, cardiac patients should pay critical attention to changes in the timing of medications, which might affect medication's adherence, considering alterations in meal timings. Indeed, it is important to consider rescheduling medicine while maintaining its therapeutic efficacy, and avoiding nearly preventable side effects due to fasting, like dehydration or hypotension. A few trials have tested this dynamic among cardiac patients on diuretics, statins, anti-coagulants, beta-blockers, and antihypertensives. Chamsi-Pacha et al. demonstrated an increased risk of dehydration when diuretics are taken before the start of fasting hours [13]. Considering that, it would be advised for post-iftar evening diuretic administration to minimize dehydration. Moreover, Almulhem et al. suggested that patients with newly prescribed statins are advised not to fast, due to aggravation of negative side effects triggered by fasting such as orthostatic hypotension [11]. Consequently, it is advised that patients on statins for a while should be taking the pill post-Iftar to target cholesterol synthesis peaks. Additionally, Lai et al. revealed that the anticoagulant warfarin is associated with an increase in the international normalized ratio (INR) mean during Ramadan fasting. However, no increase in the risk of bleeding or thrombotic events was reported, especially that a flexible range of INR is usually permitted and the absolute increase in the mean INR is not clinically significant [23]. Hence, it is advised that warfarin and other anticoagulants be taken at fixed times. Last but one, Alper et.al indicated that fasting associated dehydration poses an increased risk of Beta-blockers adverse reactions [24]. Thus, we recommended to schedule beta-blockers with Iftar to avoid morning dehydration-associated adverse events. Lastly, antihypertensives were shown to be of low risk when associated with Ramadan fasting, not to mention fasting's reported positive effects on lowering blood pressure, especially the systolic component. In light of that, Suhoor doses of antihypertensives are expected to improve their efficacy during fasting hours with no expected harm [25].

These studies taken together depict the need for medication scheduling based on fasting, Iftar and Suhoor times, with pre-Ramadan adequate consultation and supervision by the physician. Drug administration timing would then become a very potential strategy for an effective optimization while limiting any unwanted and adverse events. However, one of the major problems identified is medication adherence during Ramadan, since patients might have difficulty with the correct timing of the drug intake, which depends on their pattern of fasting based on their geographical area. Having said that, failure to optimize drug timing may result in adverse outcomes, especially in patients on tight control of blood pressure or anticoagulation therapies. Thus, it is an acceptable cause to recommend against fasting in such patients. Table 3 summarizes the impact of Ramadan fasting on aforementioned medications, and subsequent recommendations.

Table 3.

Impact of Ramadan fasting on medication effects and our recommendations.

Study reference	Medication class	Key observations	Recommendations
Almulhem et al. (2020) [11]	Statins	Patients with newly prescribed statins advised not to fast (negative effect)	Statins should be taken post-Iftar to target cholesterol synthesis peaks in those taking stable doses
Chamsi-Pasha et al. (2016) [13]	Diuretics	Increased risk of dehydration when taken during suhoor	Evening (Iftar) administration advised to minimize dehydration.
Lai et al. (2014) [23]	Anticoagulants	Increase in Warfarin INR mean during Ramadan No increase in bleeding or thrombotic events in fasting patients on warfarin	Warfarin and other anticoagulants should be taken consistently at fixed intervals
Alper et al. (2021) [24]	Beta-blockers	Fasting associated dehydration increases the risk of adverse reactions	Schedule beta-blockers with Iftar to avoid dehydration induced dizzy spells
Jahrami et al. (2021) [25]	Antihypertensives	Risk free with fasting, has positive effects on lowering blood pressure.	Suhoor dosing improves efficacy during fasting hours.

2.4. Lifestyle modifications

Changes in lifestyle during Ramadan regarding diet, hydration, and exercise have a great impact on the overall cardiac health. It is emphasized that meals should be balanced at Suhoor and Iftar, physical activity should be moderate during non-fasting hours, and adequate hydration should be attained throughout the night. For instance, Abdelrahim et al. revealed a significant reduction in the total calories, protein and carbohydrates with Ramadan fasting. However, there was no significant change in Acceptable Macronutrient Distribution Range (AMDR), which is expressed as a percentage of intake for each energy source from the total consumption [26]. Consequently, it is important to consider Ramadan fasting as an opportunity for improvement in the overall dietary consumptions and the quality of food being consumed, rather than being merely a change in meal timing. Indeed, Hammoud et al. demonstrated that caloric intake during iftar has a high influence on HDL, LDL and triglyceride levels, and may mitigate the projected effect of fasting on the lipid profile [15], while Castillo et al. indicated that excessive food consumption of a high-caloric and sugar-rich nature during Iftar diminishes possible improvements by showing an increase in triglycerides, thereby leading to weight gain [27]. Hydration is another important aspect of fasting that captures attention, especially in athletes. For instance, Attarzadeh Hosseini et al. reflected a near consensus in the literature regarding an overall decreased fluid intake- especially in athletes- during Ramadan fasting. This was attributed to the change in mealtime, along with reduction in the metabolic resting time, and reduction in hours allocated for drinking water [28]. This is especially important, as dehydration during fasting has been linked to declining aerobic performance and cognitive function [29]. Hence, it was advised to comply with the drinking pattern of 4-2-2 glasses at Iftar, Midnight, and Suhoor respectively [29]. Nevertheless, since the overall physical activity is reduced in Ramadan, it may compensate for the effect of fasting on water intake. Lastly, regarding exercise, Rouhani et.al showed that fasting along with continuing the regular outdoor activity resulted in significant weight loss in men. However, this was not observed in women due to the fact that most Muslim women are housewives, and they have lower average activity level than men [7]. Consequently, Light walking and low intensity exercise are advised during fasting for more beneficial outcomes. Additionally, it was shown that the majority of physical performance parameters were not significantly influenced by Ramadan fasting. Yet, optimizing sleep and nutrition is vital to avoid aggregating fatigue [30]. Furthermore, light exercise could be in the form of Taraweeh prayers (ritual prayers performed at night after Iftar). Indeed, it was shown that diabetic patients who participated in such prayers had more reduction in HbA1c and weight loss compared to those who did not [31].

In a nutshell, these findings point toward the optimization of health benefits from Ramadan fasting, which is especially true for cardiac patients. By which, a minimum risk is expected, if any, when dietary habits are balanced, hydration is adequate, and light physical activity is maintained. This would guarantee a balanced approach during Ramadan for both physical and spiritual well-being. Table 4 summarizes the effects of lifestyle modifications on cardiac health during Ramadan fasting.

Table 4.

Effects of lifestyle modifications on cardiac health during Ramadan and recommendations.

Study reference	Focus	Observations	Recommendations
Rouhani et al. (2014) [7]	Physical activity	Continued outdoor activity with fasting leads to weight loss	Light walking is recommended during non-fasting hours.
Hammoud et al. (2021) [15]	Diet	Caloric intake at Iftar influenced LDL, HDL and triglyceride levels	Avoid high-calorie meals at Iftar; focus on nutrient-dense foods.
Abdelrahim et al. (2024) [26]	Diet	Significant reduction in total calories, protein and carbohydrates with Ramadan fasting, no change in AMDR	Consider Ramadan fasting as not a merely change in meal timing, but rather a change in dietary consumptions and quality of food consumed, avoid high fat, sugary food at iftar.
Attarzadeh Hosseini et al. (2013) [28]	Hydration	Decreased fluid intake in athletes during Ramadan fasting, due to a change in the meal timing along with reduced metabolic resting time	Since overall physical activity is reduced in Ramadan, it can compensate for the overall effect of fasting on water intake.
Sunardi et al. (2022) [29]	Hydration	Fasting triggered dehydration is linked to declining aerobic performance and cognitive function	Drinking pattern of 4–2-2 glasses
Abaïdia et al. (2020) [30]	Physical activity	The majority of physical performance parameters are not influenced by Ramadan fasting	To reduce the risk of building up fatigue, it's important to optimize both sleep and nutrition.

3. Clinical implications

This review provides some clinically useful take-home messages about the management of cardiac patients during Ramadan. In essence, a stable cardiac patient can safely observe Ramadan fasting with appropriate adjustments in diet, hydration, and pharmacotherapy. The findings also point out the need for patient education. For instance, many patients fast despite medical exemptions, and the reasons are often spiritual. Counseling in a culturally sensitive manner can balance religious observance with health preservation, ensuring that the patients make informed decisions, especially that there is no obligation in Islam for patients with medical illness to fast. Lastly, we call for structured education programs tailored to the cardiac patients matched to the Ramadan Education and Awareness in Diabetes (READ) program, which was shown to improve body weight, decrease incidence of hypoglycemic events and better self-management skills [32].

4. Limitations and future research

A number of limitations were encountered in this review. First, heterogeneity with respect to designs, populations studied, and durations of fasts among the included studies do exist, which renders generalization difficult. Secondly, most of the studies have used short-term observations; hence, long-term effects of Ramadan fasting on cardiovascular disease are still to be revealed. Thirdly, regional diversity in eating behaviors might have an impact on the results, which therefore calls for further studies addressing such aspects. Further studies are hence required, possibly directed at large-scale multicenter trials, to assess the chronic effects of Ramadan fasting on cardiovascular health. Again, there will be a need to study any added value brought by newer technologies, such as wearable devices with AI technology, namely for continuous blood pressure monitoring and heart rate variability, which would enhance the patient safety during fasting.

5. Conclusion

This review discussed the complex relationship between Ramadan fasting and cardiac health, including its effect on various cardiac conditions, high risk group identification, medication adherence, and the impact of lifestyle modifications. The results indicate that the majority of patients with different cardiac conditions did not develop any significant adverse effects and thus could safely practice fasting during Ramadan. On top of that, Ramadan fasting was linked to improvements in multiple aspects such as the lipid profile, systolic blood pressure, and body weight. However, the findings emphasize the importance of individualized care with close monitoring during Ramadan for all high-risk individuals. Such personally tailored medication adjustments, dietary planning, and lifestyle changes will maximize benefit while minimizing any potential risks that might be associated with fasting. As such, there is a pivotal role of pre-Ramadan evaluation with culturally sensitive counseling to assist the patient in making informed choices regarding their desire to fast. The findings also provided a base to build a more comprehensive solid foundation guidelines on the management of cardiac patients during Ramadan in the future. Finally, we call for further studies looking at the long-term effects of fasting on the different cardiovascular diseases.

CRediT authorship contribution statement

Alaaeddine El Ghazawi: Writing – review & editing, Writing – original draft, Methodology, Data curation, Conceptualization. Dunia Alhareth: Writing – review & editing, Writing – original draft, Methodology. Marwan Refaat: Writing – review & editing, Supervision, Project administration, Methodology, Investigation, Conceptualization.

Ethical statement

This research required no IRB approval.

Funding

This research received no external funding.

Declaration of competing interest

The authors declare that this review paper was not influenced by any competing financial gain or personal relationship. Moreover, this study did not require the Institutional Review Board (IRB) approval since it is merely a literature review with no inclusion of human subjects.