Every morning at 7:30 a.m., Irene laces up her sneakers and heads out for a brisk walk in her neighborhood park in Florida. At 76, she swears by her daily routine. “The air is fresh, my mind feels clear, and I always come back feeling energized,” she says. Irene might not know it, but her habit perfectly aligns with new research that suggests morning workouts could be uniquely beneficial for heart and lung health in older adults.
A recent study published in Medicine & Science in Sports & Exercise tracked 799 adults with an average age of 76. Researchers used wearable devices to monitor participants’ daily activity levels over a week and performed cardiopulmonary exercise testing to assess heart and lung performance. The results? Those who were most active in the morning showed better cardiorespiratory fitness and more efficient walking patterns.
Interestingly, it wasn’t just the morning movement that made a difference. The study also found that people who exercised consistently at the same time each day—regardless of the hour—enjoyed better overall health outcomes. In other words, building rhythm and routine into your activity matters just as much as the time you do it.
But why would exercise timing impact health in the first place?
According to Dr. Karyn Esser, senior author of the study and professor at the University of Florida College of Medicine, the answer might lie in our body’s internal clock—our circadian rhythm. This biological system governs everything from body temperature to hormone release and sleep cycles. And exercise, it turns out, can influence or even reset that clock.
“Depending on the time of day, your body might respond to exercise in very different ways,” says Esser. “Your muscles could function better, your energy systems may work more efficiently, and your overall metabolic response might be stronger.” In other words, your 30-minute jog at 8 a.m. could have a very different effect on your body than the same jog at 8 p.m.
However, not everyone operates on the same internal schedule. We each have a “chronotype”—a biological inclination to be more alert in the morning, afternoon, or evening. Dr. Matthew Sedgley, a sports medicine physician with MedStar Health, emphasizes the importance of understanding your own rhythm. “Some people thrive in the morning, others are stronger and more focused in the evening. Listen to your body,” he advises.
Take Michael, a 59-year-old architect from New York, for example. He’s a self-proclaimed night owl who hits the gym around 5 p.m. every day. “I can’t even think straight in the morning, let alone lift weights,” he laughs. “But after work, I feel sharp and strong. That’s when I push myself the hardest.” And his routine works—his cardio metrics and blood sugar levels are excellent.
Of course, this isn’t the first study to highlight the potential benefits of morning exercise. A 2023 paper published in the European Heart Journal found that being most active between 8 a.m. and 11 a.m. was associated with the lowest risk of cardiovascular disease and stroke, particularly in women.
On the other hand, research has also shown benefits to afternoon and evening workouts. Some studies suggest that later-in-the-day exercise may better control blood sugar, improve insulin sensitivity, and even be linked to lower overall mortality rates. In fact, your muscles’ mitochondria—the tiny energy factories in your cells—may be more active in the afternoon, giving you a potential performance edge.
So, what’s the takeaway here?
The American Heart Association recommends at least 150 minutes of moderate-intensity exercise per week or 75 minutes of vigorous activity. But if that sounds daunting, recent findings show that even 20 minutes of weekly activity can deliver significant cardiovascular benefits.
Dr. Sedgley urges people not to get caught up in the “perfect time” to exercise. “The key is to move—regularly and consistently. The time of day is secondary to building a habit,” he says.
Dr. Cheng-Han Chen, a cardiologist at MemorialCare Saddleback Medical Center, echoes the sentiment: “Having a steady schedule is more important than squeezing in a workout at sunrise if that’s not sustainable for you.”
Still, if your schedule is flexible, morning might offer a slight edge—especially for older adults. For Irene in Florida, her morning walks aren’t just about fitness—they’re part of what keeps her vibrant, focused, and grounded.
Science may continue to explore the nuances of exercise timing, but the core message remains simple: move often, move consistently, and find a rhythm that works for you. Because at the end of the day—or perhaps the start of it—what matters most is that you move.