Effects of overnight fasting on handgrip strength in inpatients.

Objective: To investigate the effects of overnight fasting on handgrip strength of adult inpatients.

Methods: A prospective clinical study enrolling 221 adult patients. The endpoints were handgrip strength obtained by dynamometry in three time points (morning after an overnight fasting, after breakfast and after lunch) and the cumulative handgrip strength (mean of handgrip strength after breakfast and lunch) in the same day. The mean of three handgrip strength measures was considered to represent each time point. A cut-off for the mean overnight fasting handgrip strength at the 50th percentile (35.5kg for males and 27.7kg for females) was used for comparisons. We registered the age, sex, current and usual weight (kg), weight loss (kg), diagnosis of cancer, nutritional status, elderly frequency, digestive tract symptoms, type of oral diet, and the amount of dinner ingested the night before handgrip strength (zero intake, until 50%, <100% and 100%).

Results: Handgrip strength evaluated after an overnight fasting (31.2±8.7kg) was lesser when compared with handgrip strength after breakfast (31.6±8.8kg; p=0.01), and with cumulative handgrip strength (31.7±8.8kg; p<0.001). Handgrip strength was greater in patients who ingested 100% (33.2±9.1kg versus 30.4±8.4kg; p=0.03) and above 50% of dinner (32.1±8.4kg versus 28.6±8.8kg; p=0.006). Multivariate analysis showed that ingesting below 50% of dinner, severe malnutrition, and elderly were independent factors for handgrip strength reduction after overnight fasting.

Conclusion: The muscular function was impaired after an overnight fasting of adult patients hospitalized for medical treatment, especially for those with low ingestion, malnourished and elderly.