Currently, I'm taking 6,000 IU/Day. The SleepRight program I'm following from Dr. Stasha Gominak, DrGominak.com helps you raise your Vit D levels to between 60-80. At this level, your body starts to heal your sleep switches which help to place you into a deeper sleep. You get baseline Vit D and B 12 levels, then you begin to increase those blood levels if you are below 60-80. I was taking 6,000, then 11,000, then 13,000 IU/day, increasing the level of Vit D3 as I received my OH25 Vit D levels. I used Dr. Gominak's calculation method to determine what I needed to take to increase my serum D3. The OH25 D3 tests were done monthly, with dosing titrated according to past and present blood levels and D3 intake. My last D3 level came in at 84, so I cut my dose down to 6,000 IU a day, and I'm hoping my next test will come back in the 60-80 range. Each person has a highly individual response to supplementation of Vit D, so you need to pay attention to it. The goal is to find your sweet spot and stay within range. Because lack of deep sleep will defer needed repairs to the body, once you increase your D3 levels to within range, 4 specific species of gut biome that depend on a steady supply of D3 will begin to flourish and to produce all 8 of the B vitamins, which then supply the raw substrate needed to increase your deep sleep. It can take a long time to heal what might have been a decades old struggle with sleep deprivation.
At one month into having my D3 levels within range, I'm starting to notice subtle, but steady changes in my sleep patterns. For example, I typically will get up 1 or 2 times a night to void, but I'm finding there are more nights where I don't get up at all. I'm still somewhat restless, but not to the point where I am wide away and can't ignore the call of nature. Interestingly, Dr. Gominak says that studies have shown that as Vit D levels decrease in older men, size of the prostate increases. Of course, BPH is a major cause of frequent urinary urges at night. She also says that one of the deep sleep switches in the brain tells the body to produce anti-diuretic hormone, which decreases urine production and allows the body to be in a deep sleep state longer without the need to urinate frequently.
Another deep sleep switch utilizes Vit B5, pantothenic acid (she does not recommend taking B5 on it's own), which is a substrate for the body to create acetylcholine, which helps paralyze the muscles during deep sleep; a vital part of reaching the repair zone. ACH, acetylcholine, is also responsible for many activities in the body including regulating heart rate and blood pressure.
I think it's fascinating. I'm going to follow my Vit D levels for the next year to see if it makes a difference. Check out her website for some great info about Vit D3, deep sleep, and host of other issues.