2.1. Participants and Group
digestive tract disorders, allergy, diabetes
CARDIOVASCULAR DISEASES, ALLERGY, RECRUITMENT, METABOLIC DISORDERS, HYPERTENSION, CEREBROVASCULAR DISEASE, DIABETES
Sixteen national top-level male cross-country skiing athletes were recruited from the Shanxi Provincial Winter Sports Management Center. The average age of all the participants was 19.4 ± 0.9 years old, and the average length of their professional athletic training careers was 7.6 ± 3.7 years. After the initial recruitment process, a baseline examination of the athletes was conducted. The exclusion criteria included a history of cerebrovascular disease, hypertension, diabetes, impaired liver/kidney function, dairy allergy, digestive tract disorders, cardiovascular diseases, and metabolic disorders. All the participants signed informed consent forms before taking part. The study was approved by the Ethics Committee of the National Institute of Sports Medicine (approval no.: 202106); International Clinical Registration Number: ChiCTR2300069187.The 16 participants were randomly divided into a C group (control, 