Baseline measurements
Baseline data were collected 1 or 2 days before the start of the event,
after a minimum resting period of 24 h. At baseline, body height and
weight (Seca 888 scale, Hamburg, Germany) were measured to calculate
body mass index (BMI). All participants completed a general
questionnaire on demographics, level of education, smoking and
medication use, and the validated Short Questionnaire to Assess Health
enhancing physical activity (SQUASH)(25). IBD walkers completed an
extended general questionnaire with additional questions on type and
extent of IBD, age of disease onset, number of flare-ups and previous
IBD-related surgeries. Participants’ heart rate was measured every 5 km
during the first exercise day using a 2-channel ECG chest band 130
system. Heart rate (HR) was used to estimate exercise intensity as a
percentage of the maximum HR (exercise intensity = measured HR /
expected maximal HR x 100%), where expected max HR = 208 –132 (0.7 x
age))(26).