Adequate sleep is needed for your bone marrow make to make efficient blood cells. Sleep is reparative and healing for blood cells and it helps your immune system stay strong. After I absorbed the shock of feeling healthy and then being told I needed a bone marrow biopsy to confirm that my routine blood work showed CLL I went through about a month of depression and felt lethargic. That was not because of my elevated white count. I was going through the classic phases of coming to terms with the new me, a person with cancer. A supposedly incurable cancer. Yet 25 years later, without treatment my CLL for the last 15 years has regressed back inside my bone marrow and my blood is perfect, even the lymphocytes are in the normal range. Regression is not considered a cure. Kind of like herpes, it can go dormant and reappear. After my initial depression I accepted my new reality as a cancer victim and began attacking life with a gusto not wanting to waste a moment on it. I took an early retirement. I didn't feel the need to rest or take naps even if physically tired from my obsessive home and community gardening projects. All that lead to a good nights sleep.
However if my CLL had advanced and I felt tired or sleepy during the day and doctor's told me to slow down and rest during the day I'd follow their advice and try to enjoy my napping.