Regulating stress levels is important for practitioners in high-stress occupations also for dealing with stressful situations in an everyday context. Regulating mental stress can also help reduce the risk of cardiac diseases. Music therapy and Resonance Breathing are found effective in treating stress-related symptoms and promoting relaxation. Anxiety and respiratory rate reduction are seen in voluntary breathe holding and guided breathing techniques. In this work, We investigated the effect of relaxing music and slow breathing on non-linear and linear measures of HRV as a potential intervention for stress reduction in a group setting. Group studies are rare. We found that Nonlinear matrices of HRV are significantly effected by slow breathing as compared to relaxing music. The complexity and unpredictability of the heart rhythm reduced during slow breathing. Our results are in line with previous findings. We also observed that the effect does not carry over to the next condition, probably it helps build the bodies reserve which is not quantifiable through HRV. Although, regular practice of slow breathing should bring changes in resting HRV over time.