For most white people, a half-hour in the summer sun in a bathing suit can initiate the release of 50,000 IU (1.25 mg) vitamin D into the circulation within 24 hours of exposure; this same amount of exposure yields 20,000 30,000 IU in tanned individuals and 8,000 10,000 IU in dark-skinned people.
However, Willson et al. maintained the same amount of MFW exposure each week for the short 2-week transition [9], three studies allowed training only in the MFW that increased gradually each week [31, 40], and three studies based on the same cohort [11, 24, 25] controlled exposure for the first 3 weeks and then allowed the participants to increase exposure as they saw fit.
We designed the shifts so that at the end of the experiment, the flies had the same amount of light exposure as their age-matched controls.
Another group of bees was subjected to a control treatment: they were restrained and kept in the same way as the trained bees and received the same amount of sensory exposure, but the sugar reward (US) was presented before the scent (CS) (backward control), thus preventing associative learning of US and CS.
These same authors found that, despite the same amount of sun exposure, Saudi Arabian autistic children had vitamin D levels about one-half that of normals controls.
The lack of between-group differences in these acclimatisation-related measures was nevertheless expected, since both groups received the same amount of heat exposure throughout the camp.
Age-matched comparisons revealed that for groups having the same amount of sun exposure, those with moderate or are physically active will have higher levels of vitamin D status, though levels in across groups remained deficient.
Also, in a recent study, children with autism had lower serum 25(OH D concentrations than did control subjects (19 vs. 33 ng/ml), despite parents of each group reporting the same amount of sun exposure.
