Physiological Nocturnal Hand Swelling: A Prospective Evaluation of Healthy Volunteers.

Purpose: The goal of this study was to quantify the variation in daily volume that is expected in the normal hand. Our hypothesis is that hand swelling occurs overnight.

Methods: Hand volume measurements of 36 healthy volunteers with no hand pathology were taken daily at 8 am, 2 pm, and 8 pm over a 3-day period. Participants were blinded to the objective of the study. Statistical analysis was performed to determine if any of the time points or patient demographics were associated with an increased change in hand volume.

Results: Thirty-six healthy volunteers with mean age of 40.9 years and mean body mass index of 24.2 kg/m were enrolled. Twenty-one volunteers were men and 15 were women. Three of the volunteers were left-handed. The key finding from this study was that the change in hand volume overnight (8 pm-8 am) is significantly different than the change in hand volume from 8 am to 2 pm and from 2 pm to 8 pm. Although there was a significant reduction in hand volume from 8 am to 2 pm, the further reduction in hand volume from 2 pm to 8 pm was not significant after correcting for the number of post hoc comparisons. In addition, demographic variables such as age, body mass index, and sex did not influence changes in hand volume.

Conclusions: Physiological hand swelling occurs overnight in individuals without active or prior hand pathology. Hand volume then decreases over the course of the day in these same individuals.

Clinical Relevance: By investigating the changes in hand volume that occur overnight and throughout the day, we gain a better understanding of the temporal relationship between hand swelling and symptoms of chronic hand disease.