Constipation is defined as having bowel movements fewer than three times per week or experiencing subjective complaints such as a sensation of incomplete evacuation, abdominal bloating, tightness, restlessness, or discomfort despite normal bowel frequency, while chronic constipation is not a disease but a symptom characterized by decreased defecation frequency, hard stools, straining, and a persistent feeling of incomplete evacuation, with its definition varying among individuals. The aim of the present study is to investigate the acute effects of a single session of classical abdominal massage on arterial stiffness, muscle oxygenation, exercise capacity, quality of life, and sleep quality in individuals with chronic constipation. At least 30 participants diagnosed with chronic constipation will be included and randomly allocated into an intervention group or a placebo group. In both groups, arterial stiffness, muscle oxygenation, exercise capacity, constipation-related quality of life, and sleep quality will be assessed. In the intervention group, all assessments will be conducted immediately before and after the massage session, whereas in the placebo group, assessments will be performed before and after a waiting period equivalent to the duration of the massage. Normality of the variables will be examined using the Shapiro-Wilk test, histograms, and detrended plots. For between-group comparisons at baseline, independent samples t-tests will be used for normally distributed variables and Mann-Whitney U tests for non-normally distributed variables, while categorical data will be compared using chi-square tests. Post-hoc comparisons will be conducted using Bonferroni-adjusted procedures, and the level of statistical significance will be set at p \< 0.05.