JMIR Publications

ABSTRACT

Background:

Exercise intensity (e.g., target heart rate [HR]) is a fundamental component of exercise prescription to elicit health benefits in cancer survivors. Despite the validity of chest-worn monitors, their feasibility in community and unsupervised exercise settings may be challenging. As wearable technology continues to improve, consumer-based wearable sensors may represent an accessible alternative to traditional monitoring and offer additional advantages.

Objective:

The purpose of this study was to examine agreement between the Polar H10 chest monitor and Fitbit Inspire HR for HR measurement in breast cancer survivors (BCS) in an exercise program.

Methods:

BCS (N=14; aged 38-72 years) were randomized to a 12-week aerobic exercise program. HR was measured via Polar chest monitor and wrist-worn Fitbit Inspire HR at 5 stages during exercise sessions: pre-exercise rest; midpoint of warm-up; midpoint of exercise session; midpoint of cool-down; post-exercise recovery. Agreement during supervised sessions was assessed using Lin’s concordance correlation coefficient (rc). Relative error rates (RER) were calculated to examine differences across exercise session stages.

Results:

Across sessions (n=200), agreement between the Polar monitor and Fitbit was highest during pre-exercise seated rest (rc=0.76, 95%CI [0.70, 0.81]) and post-exercise seated recovery (rc=0.89, 95%CI [0.86, 0.92]), followed by the midpoint of exercise (rc=0.63, 95%CI [0.55, 0.70]) and cool-down (rc=0.68, 95%CI [0.60, 0.74]). Agreement was lowest during warm-up (rc=0.39, 95%CI [0.27, 0.49]). RER ranged from -3.91% to 3.09% and were greatest during warm-up (RER=-3.91±11.92%).

Conclusions:

While Fitbits may be utilized estimate of exercise HR, precautions are needed when considering participant safety and data interpretation. Clinical Trial: NCT03980626