What does the rhythm of your life have to do with health? Maybe a lot

On Nutrition

You probably know that eating a healthy diet, engaging in regular physical activity, not smoking and managing stress contribute to cardiovascular health. But have you ever thought about what the rhythm of your daily life might do for your risk of cardiovascular disease? A study published in the Journal of the American Heart Association in December found that your rest-activity rhythm — your daily 24-hour pattern of activity and rest (including sleep) — may also matter.

The study included 4,521 adults, average age 49, who participated in one week of physical activity monitoring as part of the National Health and Nutrition Examination Survey. Study participants who had rest-activity rhythms that were stable and less fragmented, with an active wake period and an earlier and more restful sleep period — so a distinct difference between wake times and rest times — were less likely to have cardiovascular disease or high blood pressure.

Stable means the hours when you’re either awake and active or resting and sleeping are fairly consistent from day to day, and that your daily rest-activity cycles are synchronized to both light-dark (day and night) cycles and to other environmental cues that regulate our biological clocks. For example, sleeping at night, being active during the day and not eating or engaging in vigorous exercise or stimulating mental or social activities close to bedtime. Less fragmented means having few nighttime awakenings and minimal napping during the day — an afternoon nap can have benefits, but if you’re needing to nap frequently, that’s a different story.

Looking at the numbers, 37% of those who had better-than-average rest-activity rhythms had high blood pressure and 6% had cardiovascular disease, compared to 50% and 13%, respectively, for those who had lower-than-average rhythms.

This was a short study, and the authors acknowledge that we need more robust research in this area. However, it adds to a body of research that suggests that when we live our lives out of alignment with circadian rhythms, it doesn’t do our health any favors. Tightly controlled studies in laboratory settings have demonstrated that forcing people into circadian misalignment affects how their bodies use energy and increases blood pressure. Researchers have also known for many years that doing shift work, especially when those shifts are irregular or at night, is associated with higher risk for high blood pressure and cardiovascular disease. Less-than-optimal rest-activity rhythms have also been linked to unhealthy blood sugar and insulin levels, and therefore with a risk for type 2 diabetes.

What this new study suggests is that factors such as increased freedom to eat and work when we want (even if that’s late in the evening), irregular bedtimes because we can’t stop watching just one or two or three more episodes of our favorite streaming show, regularly snoozing our morning alarms and having a lackadaisical attitude toward eating consistently through the day ultimately aren’t in our best interest.

The study authors noted that their finding that a more active wake period is related to lower cardiovascular risk is consistent with the results of studies aimed at increasing daytime physical activity. This includes “formal” exercise as well as reducing sitting time and incorporating small bouts of movement into daily routines. If reading this makes you realize that your daily rhythms may be a bit chaotic, you can choose to be more active during the day and improve your sleep habits. And if you struggle with sleep and circadian rhythm disrupters such as insomnia or night eating syndrome, you can seek professional help to address them.