Smart-watches and wearables are becoming more and more popular and this popularity is resulting in an increased interest in their use in research and clinical settings for monitoring physical activity. The battery life of these devices is of some concern, especially when they are put under increased duress through the need to constantly sample from their accelerometers. In this paper a novel approach to sampling from the accelerometer is explored whereby the accelerometer is sampled in intervals to avoid constant sampling. Results show that through reducing the sampling time and sampling in discontinuous intervals that outcome measures of time spent in sedentary, moderate and vigorous activity can be reconstructed to within acceptable error levels when compared to the same outcome measures calculated from continually sampled data.