Sleep-Aligned Fasting May Support Overnight Heart Health, Early Study Suggests

What's new

A recent study suggests that synchronizing eating patterns with sleep, specifically by fasting for several hours before bedtime, may contribute to better overnight heart health [1]. This concept, dubbed "sleep-aligned eating," involves stopping food intake approximately three hours before going to sleep, leading to an overnight fasting period of 13 to 16 hours [1]. Researchers observed that participants adhering to this schedule experienced lower heart rates, reduced diastolic blood pressure, and decreased cortisol levels during sleep, indicating a more relaxed cardiovascular state [1]. The study also noted a more pronounced difference between daytime and nighttime heart rates, which could signify a stronger circadian rhythm in cardiovascular function [1]. These findings highlight the potential importance of meal timing in relation to the body's internal clock for maintaining cardiovascular well-being.

The science behind it

The study, supported by the NCATS Clinical and Translational Science Awards (CTSA) Program, investigated the impact of time-restricted eating (TRE) when aligned with an individual's circadian rhythm [1]. While previous TRE research often focused on metabolic benefits, this study specifically examined the effects during the sleep period, an area often overlooked [1]. Participants, who were generally overweight and at risk for diabetes, followed a sleep-aligned eating schedule for 6 to 7 weeks [1]. They also dimmed lights before bed, a factor known to influence cardiometabolic health [1]. Wearable devices and laboratory measurements were used to track glucose levels, cardiac function, blood pressure, cortisol, and insulin sensitivity [1]. The observed reductions in heart rate, diastolic blood pressure, and cortisol during sleep suggest a beneficial physiological response to this eating pattern [1]. Although the primary outcome of improved insulin sensitivity was not significantly met, the cardiovascular changes were notable [1]. The researchers emphasize that sleep is an active period for bodily regulation, including cardiovascular and metabolic processes, and that aligning eating with this natural rhythm could optimize these functions [1].

What it means in practice

While these findings are from an early study and do not yet form the basis for broad clinical recommendations, they suggest a simple, cost-free intervention that individuals might consider [1]. The core practical takeaway is to aim to stop eating approximately three hours before bedtime [1]. Additionally, being mindful of evening light exposure by dimming lights before sleep is also suggested, as it can influence cardiometabolic health [1]. This approach could potentially support long-term heart and metabolic health by working with the body's natural circadian rhythms [1]. If future, larger studies confirm these benefits, sleep-aligned eating could become an accessible strategy for reducing cardiovascular and metabolic disease risk [1].

Caveats

This research is considered an early study, and its findings are not yet sufficient to support widespread clinical recommendations [1]. The study involved a specific population (overweight individuals at risk for diabetes) and a relatively short intervention period (6-7 weeks) [1]. While promising, the results need to be confirmed in larger, more diverse populations, including those with existing conditions like type 2 diabetes or higher cardiovascular risk [1]. Future research will also need to explore how factors such as sex, age, and individual sleep patterns might influence the outcomes [1]. The primary outcome of improved insulin sensitivity was not significantly achieved, indicating that further investigation is needed into all potential metabolic effects [1].

Source: [1] http://ncats.nih.gov/news/news-events/sleep-aligned-fasting-may-support-overnight-heart-health