Are Wearables Really an Accurate Index for the Physical Activity Needed for Good Health?
Medical research shows good health is promoted by adequate exercise, limited sitting and sufficient sleep. This study compared records from medical research devices that track physical activity with consumer wearables to see if the wearables accurately measure the important aspects of activity in a 24-hour period. Subjects wore nine devices simultaneously for 24-hours, including a full waking day and a full night of rest. Devices were compared for measurement of exercise, sitting time, light activity, sleep and steps taken.
Consumer devices did not provide the same output as the research devices–with two exceptions. The Lumoback device did accurately record sitting time and the research device (Actigraph GT3x+) accurately measured sleep time. Many of the consumer wearables tested did not measure all of the 24-hour activity cycle. Yet, these are important measures of health. This research should be updated so that this rapidly changing technology can be evaluated as it evolves. The addition of accurate heart rate should improve the ability of consumer devices to measure the 24-hour activity cycle.
View the abstract or contact the investigator.
Caffeine May Increase Cardiovascular Risk During Exercise
Regular exercise is known to be good for heart health, but the risk of a heart attack temporarily increases during an exercise session. Most heart attacks and strokes are caused by a blood clot that disrupts blood flow to the brain or heart. During exercise, there is an increase in the amount of certain proteins in the blood that promote blood clot formation. At the same time, there is typically an increase in other proteins that are responsible for dissolving a clot. It is believed that this balance between clot formation and dissolution is important for preventing a heart attack. Caffeine is widely consumed by many people and can be used to improve athletic performance. However, caffeine may affect the heart and blood vessels in ways that are not healthy for some people.
This recent study conducted by scientists at Ball State University studied 48 young healthy men, evaluating the effect of caffeine on markers of blood clotting potential–with measures taken before and after exercise. This study showed that a single dose of caffeine increased blood clotting activity during exercise more than a placebo, but caffeine did not affect the proteins that dissolve blood clots. These results suggest caffeine may cause changes in the blood that promote clot formation and, thus, increase cardiovascular risk during exercise.
View the abstract or contact the investigator.
Is Weightlifting Good for Your Heart? If Yes, How Much Is Enough?
Aerobic exercise, such as running, reduces the risk of cardiovascular disease events like heart attack or stroke; thus, it is commonly called “cardio” exercise. Weightlifting has been traditionally considered to improve sports performance in athletes. Yet, limited evidence exists to clarify whether weightlifting reduces heart attack or stroke risk, which represents major causes of death in the general population. In this study, the researchers investigated the possible relationship between resistance exercise with the risks of developing cardiovascular disease and premature death.
Preventive health exam records of 12,591 adults (average age 47) provided the data for this study. The study found even doing weightlifting exercises one time per week (or less than one hour/week) reduced the risk for a heart attack or stroke by 40-70 percent. This was true regardless of whether or not the subjects reported participating in aerobic exercise! This study fills an important knowledge gap about the benefits of weightlifting–supporting that it may reduce risk of heart attack or stroke, beyond the well-documented benefits of aerobic exercise.
View the abstract or contact the investigator.
Resilient Female Hormone Function after Record-Breaking Antarctic Crossing!
Women are thought to be biologically sensitive to effects of extreme physical activity when accompanied by weight loss–possible negative consequences cited include bone fractures and fertility difficulties. Scientists from the University of Edinburgh and the Royal Centre for Defence Medicine, United Kingdom, examined the effects of an extreme challenge in six women who skied over 1,000 miles in 61 days, while pulling sleds weighing about 176 pounds. All in an environment of very low temperatures and high winds. The investigators monitored several health markers before and after the expedition, including stress, reproductive and metabolic function and fat and muscle levels.
Findings indicated that muscle levels and hormone markers of stress, fertility and bone strength were preserved, despite enduring such extreme exercise and losing on average 22 pounds in body fat. Some tests even showed evidence of exercise-related benefits by two weeks after the expedition had ended. These findings contain some potentially myth-busting data on the impact of extreme physical activity on women. These investigators have shown that, with appropriate training and preparation, many of the previously reported negative health effects of such challenges can be avoided. The low number of highly-selected women means the findings may not be applicable to all. More research is needed to compare these measures in women with men, and to explore whether factors like dietary content, adequate sleep or psychological preparation might have protected women against the negative effects of extreme exercise with weight loss.
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