More Muscle, More Sleep
In this edition of The Rundown, a fitness tracker is recalled, it's resistance training over aerobics for better sleep and physical activity reduces the risk of Alzheimer's disease.
Fitbit Ionic Recall. Fitbit, in association with the U.S. Consumer Product Safety Commission (CPSC) is recalling Fitbit Ionic smart watches sold between 2017 and 2020. The fitness trackers have a colored LCD display, three buttons and model number FB503 on the back. In the U.S., there have been reports of at least 115 incidents of batteries overheating. The CPSC website says there were also 78 reports of actual burn injuries. Fitbit is issuing the recall “out of an abundance of caution” but advises customers to stop using the Ionic. A refund registration page is available on Fitbit’s website.
More Muscle, More Sleep. A new preliminary study presented at the American Heart Association’s Epidemiology and Prevention, Lifestyle and Cardiometabolic Health conference on March 3 says that resistance exercise may be better than aerobic exercise for improving the duration and quality of sleep.
For the study, which lasted a year, researchers randomly assigned 386 inactive, overweight adults with high blood pressure to either a no-exercise group (for comparison) or one of three exercise groups: aerobic only, resistance only, or combined aerobic and resistance. The participants worked out three times a week in supervised 60 minute sessions. (The combined aerobic/resistance group did 30 minutes of each type of exercise).
The aerobic group maintained a prescribed heart rate range for moderate to vigorous intensity exercise. The resistance group completed their sets (3) and repetitions (8-16) on 12 resistance machines in order to work all major muscle groups in a session. The combination group did 30 minutes of aerobic exercise at moderate to vigorous intensity and two sets of 8 to 16 repetitions on nine machines. Self-reported questionnaires at the beginning of the study and at the end of one year measured all the exercisers’ total sleep quality, sleep duration, the time it took to fall asleep, the time they spent in bed and the number and frequency of sleep disturbances.
At the start of the study, 42% of participants were getting less than seven hours of sleep. Among this group, sleep duration increased by an average of 40 minutes for those doing resistance exercise. For the aerobic exercisers, sleep increased by 23 minutes. Sleep duration rose 17 minutes for the combined group and 15 minutes for the control group. The resistance group also found that it took three minutes less to fall asleep each night. The results are considered preliminary until the full findings are published in a peer reviewed journal.
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Exercise Lowers Alzheimer’s Risk. Doctors at the Washington VA Medical Center in Washington, D.C. have linked physical activity with a reduced risk of developing Alzheimer’s disease. Their study (read the abstract) involved 649,605 military veterans in the Veterans Health Administration database who did not have Alzheimer’s disease. Their average age was 61 and they were followed for an average of nine years.
All participants took a treadmill test to determine their cardiorespiratory fitness and were then divided into five groups, from least fit to most fit. The treadmill test measures exercise capacity or the highest amount of physical exertion a person can sustain. Cardiorespiratory fitness is a measure of how well your body transports oxygen to your muscles and how well your muscles absorb oxygen during exercise.
The least fit group developed Alzheimer’s disease at a rate of 9.5 cases per 1,000 person-years. (Person-years account for the number of people in a study and the amount of time spent in the study). The most fit group developed Alzheimer’s at a rate of 6.4 cases per 1,000 person-years. When the clinicians adjusted for other factors that could impact the risk of developing Alzheimer’s disease, they discovered that the participants in the most fit group were 33% less likely to develop the condition than those in the least fit group.
A limitation of the study is that the participants were mostly white men so the results may not be generalizable to other populations. The preliminary findings will be presented at next month’s American Academy of Neurology’s 74th Annual Meeting.