Effects of Water-Based Exercise on Cardiometabolic-Related Proteins and Physical Fitness in Older Adults

Research Objectives: To investigate correlations between changes in cardiometabolic plasma protein concentrations and markers of physical fitness following high-intensity water-based exercise training with older adults.

Design: Secondary analysis of a single-arm trial, using paired-sample t-tests and Pearson’s correlations.

Setting: Veterans Affairs Hospital, Palo Alto, CA.

Participants: A volunteer sample of 20 older adults, ages 55-82 years old (mean 68.15±7.75), recruited for their ability to perform exercise training, and screened for acute or unstable chronic illnesses (including severe cardiac and respiratory disease).

Interventions: Participants engaged in supervised aquatic exercise training for six months, with target intensities of 70-80% heart-rate reserve for 45 minutes, thrice-weekly. Maximal graded cardiopulmonary exercise testing (CPET), 6-minute walk test (6MWT), and blood samples were assessed at baseline and post-intervention.

Main Outcome Measures: Activity-dependent changes in: 1) indices of physical function (VO2 max, 6MWT, resting heart rate and blood pressure); and, 2) plasma protein concentrations (analyzed via the Olink Taget 96 Cardiometabolic assay [Uppsala, Sweden]).

Results: Participants significantly improved VO2 max (t = -2.123, p= .048) and distance walked on the 6MWT (t = -2.326, p= .032), with significant reductions in protein concentrations for angiopoietin-related protein 3 ([ANGPTL3]: t = 3.081, p= .006), peptidyl-glycine alpha-amidating monooxygenase ([PAM]: t = 3.175, p= .005), and trypsin-2 ([PRSS2]: t = 2.660, p= .015). Correlational analyses indicated PRSS2 was the only marker significantly associated with physical fitness (6MWT: r= -.556, p= .013).

Conclusions: Aquatic exercise training significantly improved several markers of cardiometabolic health in older adults. Results highlight the benefits of late-life exercise and present novel biological mechanisms involved in physical fitness. While PRSS2 has been associated with medical disorders (e.g., pancreatitis, cancer), this is the first study to demonstrate activity-dependent changes related to improved physical functioning. Future studies should investigate these biomarkers as potential therapeutic targets, utilizing larger sample sizes, control groups, and different exercise modalities.

Author(s) Disclosures: The authors have no disclosures or conflicts of interest to declare.