Three studies that examined the impact of RD-led dietary intervention for heart failure patients found that with two or more visits, patients reported reductions in sodium and fluid intake and improvements in quality of life. One study found a reduction in urinary sodium excretion, extra-cellular water, edema and fatigue and increases in physical activity. Two studies reported RD-led interventions involved an initial planned visit that lasted 45 minutes and follow-up visits lasting 30 minutes over a six-week to nine-month time period. Data on long-term adherence and sustained diet and physiological responses are unavailable. The optimal duration and frequency of follow-up visits by a RD is not known.