2018, Volume 14
Effects of different periods of rapid weight loss on dehydration and oxidative stress
Mio Nishimaki1, Hiroki Tabata2, Masayuki Konishi3, Stefan Pettersson4, Shizuo Sakamoto3
1Department of Sport Sciences, Japan Institute of Sport Sciences, Tokyo, Japan
2Waseda University, Graduate School of Sport Sciences, Saitama, Japan
3Waseda University, Faculty of Sport Sciences, Saitama, Japan
4University of Gothenburg, Department of Food and Nutrition, and Sport Science, Gothenburg, Sweden
Author for correspondence: Mio Nishimaki; Department of Sport Sciences, Japan Institute of Sport Sciences, Tokyo, Japan; email: email@example.com
Background and Study Aim: Many athletes will lose weight 5% or more within 7 days. Many reports have been published on the negative health effects of rapid weight loss (RWL) in wrestlers. This study aims to examine the effects of different periods of RWL on dehydration state and oxidative stress.
Materials and Methods: Participants were nine male collegiate wrestlers who reduce their body mass by 5% within 7, 3, or 1 day in randomized order using the same methods. They have experienced (7-day, 3-day, and 1-day) weight loss separated by more than 4 weeks. All participants reduced 5% of their body mass in all trials. Following the weight loss, they tried to regain all of their lost weight with an ad libitum diet for 14 h. Body composition and biochemical variables were measured at baseline and immediately after weight loss and weight regain.
Results: There were no statistically significant differences in hematocrit, serum sodium, chloride, potassium, calcium, osmotic pressure, and antidiuretic hormone. For plasma aldosterone concentrations and plasma d-ROMs concentrations, two-way analysis of variance revealed the main effect of time (P < 0.05). RWL (loss of 5% of body weight within 7 days) is surmised to have increased oxidative stress via dehydration and elevated levels of aldosterone.
Conclusions: Although different weight loss periods did not yield any changes, RWL of 5% of body weight was suggested to increase oxidative stress.
Key words: rapid weight loss, dehydration, oxidative stress