A wave of new research warns that exercising too late in the day—especially if it’s high-intensity—could be robbing you of restorative sleep. As more Thais embrace fitness culture and nighttime gyms gain popularity in Bangkok and beyond, a landmark study of nearly 15,000 people has highlighted how the timing and intensity of your evening workout could be the culprit behind tossing, turning, and groggy mornings (Fortune, Nature Communications). For many, it’s a challenge to find gym time amid work, family, and Bangkok’s notorious traffic jams, pushing workouts close to bedtime. But these new findings have direct and important implications for health-conscious Thais.
Historically, regular exercise is one of the pillars of a healthy lifestyle, lauded by doctors and public health agencies worldwide—including Thailand’s own Ministry of Public Health—for reducing risk of disease, boosting mental health, and even improving sleep quality. However, research led by teams at Monash University and published in Nature Communications has upended the blanket advice that “any exercise is good exercise”—at least when it comes to sleep. The study tracked 14,689 active adults with fitness trackers over a year, analyzing over four million nights of data. The key takeaway: the closer you finish your workout to bedtime—especially if it’s intense, such as a HIIT session or a long run—the more you’re likely to experience disrupted sleep (MSN, New Atlas).
Participants who wrapped up high-strain workouts less than four hours before sleep faced delayed sleep onset, shortened sleep duration, lower sleep quality, and more disturbed nighttime heart rhythms. “Evening exercise—particularly involving high levels of cardiovascular strain—may disrupt subsequent sleep and nocturnal autonomic function,” the researchers concluded. By contrast, those whose workouts ended at least four hours before bedtime, or who stuck to lighter activities like stretching or walking in late hours, did not see significant sleep disruption (Nature Communications, 2025).
Dr. Sean Cain, a sleep researcher at Monash University and co-author of the study, explained, “The adrenaline and higher core body temperature from a strenuous workout can make it much harder to wind down and fall asleep. Biologically, your body is still primed for action, not for rest.” This aligns with longstanding understanding of how elevated heart rate and sympathetic nervous system activity interfere with sleep cycles, particularly the deep REM stages crucial for memory, mood, and muscle repair (Medical Xpress, Wikipedia).
For many urban Thais, the convenience of 24-hour gyms, rooftop fitness classes, and late-running Lumpini Park jogs has made evening exercise the norm—especially for office workers coping with long commutes. Social media influencers, too, often share late-night fitness routines. But experts caution that this trend, already prominent in cities like Bangkok and Chiang Mai, may come at a hidden cost if not carefully timed.
Thailand has its own sleep crisis: surveys repeatedly show that insomnia and poor-quality sleep are common, especially in cities. The National Statistical Office reported in 2023 that over 30% of Thais experience regular sleep difficulties, impacting everything from productivity at work and school to mental health and traffic accident rates (Xinhua). Added to this are cultural pressures to “krengjai”—putting work and others’ needs first—even at the expense of personal wellbeing.
The latest global research dovetails with Thailand’s context, illustrating not only the universality of the late-workout-sleep conundrum but pointing toward practical changes. For teachers and parents, it raises fresh questions about late sports practices and after-school fitness clubs. For working adults, it suggests a rethinking of when and how to squeeze in movement. Even monks and temple communities, who increasingly promote meditation and gentle exercise in the evenings, may consider these findings in their wellness programs.
Contrary to the myth that only vigorous, sweat-inducing sessions count as real exercise, the new evidence suggests lighter, more relaxing activities—such as evening yoga, tai chi, or a stroll in a well-lit park—are better bets within four hours of bedtime. Dr. Surapong Suwankesorn, a Bangkok-based sleep medicine specialist, notes: “We see many patients struggling with sleep without realizing the root is their workout timing. The body needs to cool down—both literally and metaphorically—before it can settle into restful sleep.” In the Thai climate, where humidity and heat already challenge thermoregulation, this advice carries extra weight.
Globally, the findings have prompted calls for major health bodies—including the World Health Organization and the American Heart Association—to update guidelines by emphasizing not just the amount, but the timing and intensity of physical activity. National campaigns in Western countries have pivoted to promote morning and afternoon exercise slots—seening boost in sleep quality, energy, and even lower risk of chronic disease when people shift their workouts earlier in the day (Gizmodo).
Thailand’s government and private wellness sectors might consider similar shifts. Minimarts and gyms could support this with flexible hours, while employers and schools could encourage earlier breaks for movement, especially for shift workers and students whose schedules now routinely stretch into the evening. Innovative fitness programs like sunrise aerobics or lunchtime dance sessions, already seen in some offices and universities, may hold the key for Bangkok’s high-rise workers and rural residents alike who want the benefits of regular activity without sacrificing rest.
Historically, traditional Thai medicine and Buddhist teachings both recognize the value of aligning daily habits with natural cycles—rising with the sun and resting when night falls. In rural communities, evening cooling down is common, often with gentle stretching or slow walks around the temple. With urbanization, artificial light, and screen time now keeping cities awake late into the night, these age-old rhythms have been disrupted—a point modern science now echoes.
Looking ahead, as Thailand seeks to address rising rates of obesity, diabetes, and cardiovascular disease—all linked to both inactivity and poor sleep—the message is clear: prioritizing both exercise and rest, and not forcing them into conflict, can unlock the best health. Future research will likely dive deeper into how genetics, age, and other factors affect sensitivity to late workouts, but the basic advice is robust.
For Thai readers wondering what to do, the practical takeaway is “ออกกำลังกายแต่ให้เลือกเวลาให้เหมาะสม”—get your movement, but time it wisely. Aim to finish vigorous workouts at least four hours before bedtime. If life can’t be changed and you must work out late, opt for lighter forms of exercise like stretching, gentle yoga, or leisurely walking. Turn down the aircon, enjoy a warm shower (to kick-start cooling), and dim screens in the hour before sleep. And if restless nights persist, don’t hesitate to seek advice from a sleep clinic—you might discover that tweaking your workout schedule is the missing piece.
With more Thais than ever making health a priority, understanding the science of sleep and movement is a vital step toward a more energetic, productive, and happy nation.
Sources:
- Fortune: Working out at this time could disrupt your sleep quality
- Nature Communications: Dose-response relationship between evening exercise and sleep
- MSN: Exercise before bed is linked with disrupted sleep
- New Atlas: Evening exercise impacts sleep for longer than previously thought
- Gizmodo: Why Your Workouts Before Bedtime Need to Stop
- Wikipedia: Effects of evening exercise on sleep quality