Inactive people should start with small amounts of physical activity and gradually increase duration, frequency and intensity over time.
缺乏活动的人在开始时应做少量的身体活动，并随时间逐步增加活动时间、频率和强度。
2
It is appropriate to start with smaller amounts of physical activity and gradually increase duration, frequency and intensity over time.
适宜的方法是，从较小的活动量开始，然后随着时间的推移，逐渐增加持续时间、频度和强度。
3
Once you get used to the process, increase the frequency and/or duration, but it’s more important that you keep at it over time than it is that you’re consistent in intensity over time.