Does Carbohydrate Mouth Rinsing Affect Six Minute Walk Test And Blood Glucose Responses In Older Adults?

Abstract

Carbohydrate mouth rinsing (MR) prior to exercise can improve performance in endurance and power activities in young physically active populations. Carbohydrate MR may also improve impulse and power during the sit-to-stand maneuver in healthy older adults; however, its effect on functional aerobic endurance and underlying physiological mechanisms are not well established. PURPOSE: To determine if carbohydrate MR affects six-minute walk test (6MWT) distance and blood glucose responses in healthy older adults. METHODS: 26 participants (12 males, 14 females) age ≥ 70 years completed the 6MWT during two testing sessions under two MR conditions: a 6.4% maltodextrin (MDX) condition and a placebo (PLAC) condition. Participants and researchers were blinded to MR contents, and MR administration was counter-balanced. Prior to testing, participants refrained from food and drink (except water) for 4 hours, as well as exercise, caffeine, and alcohol for 12 hours. Testing sessions occurred at the same time of day, separated by at least 48 hours. Participants held the MR in their mouth for 20 seconds, returned it to a vial, and immediately completed the 6MWT. Total distance walked and rating of perceived exertion (RPE) during the 6MWT were compared between MR conditions using paired sample t-tests. Blood glucose and lactate levels were compared pre- and post-6MWT and between MR conditions using 2x2 repeated measures ANOVAs. RESULTS: Total distance walked and RPE were similar between MR conditions (481 ± 79 m vs. 485 ± 70 m, p = 0.33 and 11 ± 3 vs. 11 ± 3, p = 0.62). Blood glucose did not significantly differ according to MR condition or time (100 ± 16 mg/dL and 102 ± 17 mg/dL for the MDX condition pre- and post-6MWT; 105 ± 26 mg/dL and 104 ± 26 mg/dL for the PLAC condition pre- and post-6MWT, p = 0.16-0.49). Blood lactate significantly increased pre- to post-6MWT, but did not significantly differ according to MR condition (1.4 ± 0.5 mmol/L and 2.7 ± 0.9 mmol/L for the MDX condition pre- and post-6MWT; 1.4 ± 0.4 mmol/L and 2.6 ± 1.1 mmol/L for the PLAC condition pre- and post-6MWT; p < 0.01-p = 0.99). CONCLUSION: Carbohydrate MR may not significantly impact functional aerobic performance in older adults. Continued research into the clinical relevance of pre-exercise MR in older adults, including the use of other variations of gustatory stimuli, is warranted.