The Rebbe stresses the importance of health for serving Hashem, advising proper eating and sleep. He encourages teaching Chassidus with engaging introductions and supports reviewing Torah broadly, including Chassidus. He advises against fasting for a dream and emphasizes Torah study. He concludes with blessings for health and requests updates.
https://www.torahrecordings.com/rebbe/004_igros_kodesh/shevat/899