Intermittent fasting alone may lead to cardiovascular and metabolic benefits (2). A meta-analysis found that intermittent fasting reduces body weight by 1.1 to 6.5 kg and improves lipid profile (3). Four- and 6-h time-restricted feedings can result in similar weight loss by 3.2% and reduce insulin resistance by 12–29% in obese individuals (4). Moreover, time-restricted feeding for 5 weeks has been found to reduce systolic and diastolic blood pressure by 11 ± 4 mmHg and 10 ± 4 mmHg, respectively, in men with impaired glucose tolerance (5).

A recent systemic review and meta-analysis also found that Ramadan fasting (RF) improved cardiometabolic risk factors that may confer short-term protection from cardiovascular disease (6). In another systemic review, all fasting regimens revealed strong evidence to support intermittent fasting as a feasible diet to improve glycemia and body composition measures in obese people with type 2 diabetes mellitus (T2DM) within 12–24 weeks (6) and redistribution of abdominal fat, although a follow-up of 12–18 months after intermittent fasting did not show promising results for continued weight loss and improved glycemic control (6). Intermittent fasting has beneficial effects on lipid profile, and it is associated with weight loss and modification of the distribution of abdominal fat in people with obesity and T2DM as well as improvement in the control of glycemic levels (7).

In a systemic review by Horne et al., there were 3 randomized controlled clinical trials of fasting in humans with results published in 5 articles; all of which evaluated the effects of fasting on surrogate outcomes with improvements in weight and other risk-related outcomes. Improvements in weight and other risk-related outcomes were found in the 3 trials. Two observational clinical outcomes studies on humans were found in which fasting was associated with a lower prevalence of CAD or diabetes diagnosis. No randomized controlled trials of fasting for clinical outcomes were identified (8).

In short, chronic intermittent fasting alone can accrue health and metabolic benefits.

Exercise and diet, either low energy intake or fasting, have positive effects on health through different pathways and mechanisms (11). There is evidence of increased fat metabolism when exercise is performed in the fasting state rather than post feeding, hence supporting the health benefits for exercise performed when fasting (12). To promote and encourage physical activeness during the RF month, we thus propose in this narrative review that low- to moderate-intensity exercise be performed in the form of WF during the daytime near breaking of fast hours in regions with long daytime fasting such as the equatorial region and summer periods. We reasoned that the combination of RF and WF will potentially augment the health benefits of fasting individuals.

Why specifically WF and not some other types of exercise?

To our knowledge, there have been only five studies published on the physiological and psychological outcomes measured from WF sessions, as shown in Table 1 (15–19).

In Table 1, WF matches were mostly played 5-a-side, suggesting the potential association of the number of players with exercise intensity. In this aspect, a smaller number of players could imply greater distance covered and, consequently, a higher level of muscle activation, since individuals are expected to cover a wider ground and be engaged with the play to a greater extent. In addition, a WF match also involves a high volume of turning and twisting and many spurts of immediate change of direction actions (i.e., very short accelerations and decelerations). Indeed, these movements could have positive effects on bone health, which is clearly beneficial to older aged participants (15).

Harper et al. found that participants developed a mean percentage of maximum heart rate of 76 ± 6% during sessions, with a rating of perceived exertion across all sessions at 13 ± 2. Blood lactate significantly increased by ~157% from pre-session to post-session. There were ~100 changes of direction per session. Hence, WF is a moderate- to vigorous-intensity activity (15).

Ayabe et al. found that the average heart rate was 127 ± 20 beats per min (82 ± 14% of the age-predicted maximum HR) in a 10-min game of WF, with a significant association to the number of plays after adjusting for age. The estimated metabolic cost was 8 ± 1.6 metabolic equivalents with a significant correlation to the maximal oxygen uptake, number of plays with a ball, and stepping rate. Hence, cardiorespiratory responses could be above the desirable levels of exercise prescribed in middle to old-aged adults with mild metabolic disorders (16). However, the authors found that their study was limited by the lack of familiarity of participants to WF, which could account for physiological stress and change with experience.

Heil et al. found that mean relative HRs exceeded the 65% threshold for improving cardiovascular fitness for both teams competing in a match. Both teams also maintained an average metabolic intensity that was statistically similar to the 3.0 MET threshold that decreases one risk for non-communicable diseases and walked an average of 2.2–2.4 km/match. Hence, this is supportive evidence for competitive WF being of sufficient intensity to promote positive changes in both cardiovascular and metabolic fitness in Southeast Asian women (17).

Arnold et al. studied a population with medical conditions such as hypertension, T2DM, knee osteoarthritis, spinal stenosis, atrial fibrillation, bronchitis, and other medical comorbidities with results that prove to be beneficial, including a significant reduction of 11% in body fat mass and in percentage body fat of 9%, and improvement in other anthropometric measures such as 2% reduction in whole body mass, 4% increase in lean body mass, and 3% reduction in body mass index (BMI). However, there was a significant increase in systolic blood pressure by 4% after the 12-week WF program, attributed to lack of medication adherence (19).

In contrast, Reddy et al. found significant greater improvement in blood pressure for players when compared to the control group (18).

In summary, playing WF has been shown to elicit sufficient exercise intensity and duration that would promote cardiovascular fitness, muscular health, and possibly bone health among regular participants of the game.

There are only two studies examining the training-induced adaptations as a result of chronic WF exercise (Table 1). The study of Arnold et al. showed that 12 weeks of WF (2 h per session once a week) among the elderly has had a positive impact on lowering body fat percentage and increasing exercise tolerance (19). However, the study was limited because no physiological data during the WF sessions were reported, and no control group was included in the study (18). The study of Reddy et al. on playing WF once a week between 45 and 60 min, on the other hand, did not show any clinical or health improvements in WF participants relative to controls, although a small positive impact on blood pressure was noted in the WF group (16). Nonetheless, the limited prevailing data on acute responses and chronic training-induced adaptations to WF activity seem to support the potential cardiovascular and clinical health benefits of WF when performed consistently or regularly across a prolonged period of time.

It should be noted that many older adults had reported a dislike for structured exercise programs (20). During WF, the movements are unstructured, unplanned, and varied. Thus, an interesting and important finding in all the five reviewed studies was that all the participants of WF have reported elevated levels of enjoyment and keen participation in this exercise form (20). Indeed, in a recent review on WF, the authors found that almost all participants in this activity believed that WF provides beneficial mental and physical effects (13). The review also reported that the factors valued the most by the participants were the collaborations among team-mates and team identity during game. The participants of the review also found that compared to visiting the gym or engaging in other regimental physical exercise programs, WF is the preferred form of physical activity. It was concluded that WF has a major positive impact on the overall sense of well-being and social connections of participants (15).

Reddy et al. surveyed a group of elderly who played WF for 12 weeks and found a very positive impact from participation with individuals experiencing high levels of excitement and enjoyment when playing (17). They also highlighted that the ability to meet and make new friends contributed to the self-reported overall improvement in their physical health and well-being (17).

In another study, McEwan et al. similarly showed high adherence to participation in a 12-month WF exercise program among middle-aged obese men (21). When evaluated for a personal perspective of the program, social interaction, group interaction to improve health, and new lease of life were the 3 main themes for continued involvement (21). The opportunity to engage in football and the link to a professional football club 21 were the top 2 factors to continued involvement. Those who participated were overweight, sedentary, exhibited blood pressures outside normal ranges, and all but two were hypertensive. Adherence to the program was 90% over 8 weeks, and of those contacted after a year, all had maintained engagement in WF. Hence, WF is a feasible and cost-effective method of recruiting and retaining men aged at least 50 years old to a physical activity program, although attrition is to be expected.

To our knowledge, there have not been studies on WF during RF. Future studies looking into health outcomes of WF in RF and the non-fasted state as well as studies comparing WF with other low-intensity exercises during RF in an age-adjusted and gender-adjusted manner would be useful to promote exercise in a more physically active Ramadan to reap the maximal health benefits from RF.