Participation and study procedures

Taking part in BRACE involves around ten to twelve weeks in total: a training phase, your half marathon and a single laboratory visit.

You may be eligible if you

• are between 18 and 50 years old,
• are healthy and do not smoke,
• have a body mass index (BMI) of at least 18 and below 30,
• plan to run a half marathon during the study period,
• own a sports watch that records heart rate and GPS data, and
• have a smartphone compatible with the BreezeTracking app.

You cannot take part if you have an ongoing injury or musculoskeletal condition, a cardiovascular or respiratory condition such as asthma or COPD, or if you have had a respiratory infection within the past two weeks. Smoking, pregnancy, breastfeeding, a BMI below 18 or of 30 and above, and health-related or language barriers that prevent you from following the study procedures are also exclusion criteria.

You train independently and complete at least 15 running sessions. You can follow your own training plan or use the structured plan available through running.COACH. In either case, all sessions must be uploaded via the running.COACH app. You download the app for this and receive three months of free access from us.

During your runs, you wear the Shokz open-ear headphones provided for the study. The BreezeTracking app on your smartphone uses the microphone signal from the headphones to estimate your breathing rate, and your own sports watch records heart rate and GPS data. Around halfway through the training phase, you complete a Graded Run: an incremental running test on a route near you. You may also choose to wear a BreezeBelt, a chest strap supplied by our project partner.

You take part in your planned half marathon and record it in the same way as your training runs: put on the headphones, start the recording in BreezeTracking and record the activity on your sports watch. Your official finish time is obtained from the race organiser. Race registration and participation are your own responsibility and are not part of the study.

Between five and 21 days after your half marathon, you attend a single laboratory appointment at the DSBG in Basel. The visit includes a health questionnaire (PAR-Q), a DXA scan to assess body composition, spirometry to assess lung function and a treadmill exercise test with respiratory gas analysis. Trained study staff supervise all assessments, and you receive a summary of your results afterwards.

There is no financial compensation for participation. Neither you nor your health insurer will be charged for the study assessments. Travel expenses for the laboratory visit may be reimbursed on request. The headphones are provided on loan and must be returned at the end of the study. Access to running.COACH is free of charge for three months.

1. Complete the registration form so that we can check whether you meet the eligibility criteria.
2. If you appear eligible, we contact you and send you the participant information and the consent form to review.
3. We arrange a short video call to answer your questions. You can then give your informed consent electronically via DocuSign.
4. We send you the headphones, your running.COACH access code and instructions, and the training phase begins.

Signing up does not commit you to participating. You decide whether to take part after the video call.

Recruitment for 2026 has closed. The next phase is planned for spring 2027. You can take part with any half marathon held during that period, such as the half marathon at the Zürich Marathon or another event of your choice. If you are interested, complete the registration form. We will add you to the waiting list and contact you when recruitment begins.

Do you know someone who might be interested? Our one-page flyer summarises the key information and can be printed or shared with running groups, clubs or friends.