Recent research has suggested that stress and anxiety levels are associated with gastrointestinal (GI) symptoms in endurance athletes (runners, cyclists, triathletes). Yet, there has been limited attempt to evaluate whether GI symptoms during running can be mitigated by interventions designed to reduce stress and anxiety. Thus, this study will evaluate the effects of four-week slow deep breathing and mindful breath counting interventions on subjective and objective measures of stress/anxiety and GI symptoms in runners with mild-to-high anxiety and that are prone to GI symptoms during runs.

Inclusion Criteria:

• At least 18 years of age
• Run at least 15 miles per week
• Access to internet
• Access to a smart phone that is compatible with iOS or Android applications
• Score at least a 5 on the GAD-7
• Report to have experienced GI symptoms "sometimes", "often" or "always" during runs in the previous month.
• If on a psychotropic medication, must be on a stable dose for the past 3 months.
• Live within the contiguous United States

Exclusion Criteria:

• Younger than 18 years
• Run less than 15 miles per week
• Do not have access to the internet
• Do not have access to a smart phone that is compatible with iOS or Android applications
• Score less than 5 on the GAD-7
• Report to have "never" or "rarely" experienced GI symptoms during runs in the previous month
• Are being prescribed a psychotropic medication and have not had a stable dose for at least three months.
• Do not live within the contiguous United States