Researchers developed a method to estimate cardiorespiratory fitness levels that could be applied to data acquired by wearable fitness trackers during daily activities. This could facilitate tests for those who have low exercise tolerance and may reduce the need for fitness tests under medical supervision.
Cardiorespiratory fitness is the ability of the cardiovascular and respiratory systems to supply enough oxygen to the muscles during physical activity. People with low cardiorespiratory form may have an increased risk of heart disease, heart attack or stroke. Testing the amount of oxygen that the body uses during exercise (VO2max) can evaluate these risks and also function as a preventive measure. However, people generally have to train until exhaustion to measure VO2max and such tests require medical supervision and specialized equipment. In addition, it may not be safe for anyone who has to undergo cardiorespiratory fitness tests to exercise at maximum effort. Methods that use low intensity (submaximal) exercise do not always provide accurate results like maximum tests.