Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

People have a pretty intuitive sense of what is healthy - standing is better than sitting, exercise is great for overall health and getting good sleep is imperative.
However, if exercise in the evening may disrupt our sleep, or make us feel the need to be more sedentary to recover, a key question emerges - what is the best way to balance our 24 hours to optimize our health?
Our research attempted to answer this for risk factors for heart disease, stroke and diabetes. We found the optimal amount of sleep was 8.3 hours, while for light activity and moderate to vigorous activity, it was best to get 2.2 hours each.
Current health guidelines recommend you stick to a sensible regime of moderate-to vigorous- intensity physical activity 2.5-5 hours per week.
However mounting evidence now suggests how you spend your day can have meaningful ramifications for your health. In addition to moderate-to vigorous-intensity physical activity, this means the time you spend sitting, standing, doing light physical activity (such as walking around your house or office) and sleeping.
Our research looked at more than 2,000 adults who wore body sensors that could interpret their physical behaviours, for seven days. This gave us a sense of how they spent their average 24 hours.
At the start of the study participants had their waist circumference, blood sugar and insulin sensitivity measured. The body sensor and assessment data was matched and analysed then tested against health risk markers such as a heart disease and stroke risk score to create a model.
Using this model, we fed through thousands of permutations of 24 hours and found the ones with the estimated lowest associations with heart disease risk and blood-glucose levels. This created many optimal mixes of sitting, standing, light and moderate intensity activity.
When we looked at waist circumference, blood sugar, insulin sensitivity and a heart disease and stroke risk score, we noted differing optimal time zones. Where those zones mutually overlapped was ascribed the optimal zone for heart disease and diabetes risk.
(Adapted from the Conversation)

Câu hỏi

According to the study, how long is the optimal amount of sleep per night?