Aim 1 will test whether a 3-month exercise program has long-term clinical benefits in acute DVT. The primary outcome measures will be Villalta score for PTS and VEINS-QOL score (Venous Insufficiency Epidemiological and Economic Study-QOL) for venous quality of life at 2 years of follow-up. Aim 2 will evaluate whether exercise therapy in patients with acute DVT enhances thrombus resolution. Aim 3 will assess the relationship between PTS, venous hemodynamics and exercise capacity.