Figure 1
Change in LH in relation to time of light exposure. Change in urinary LH excretion (mIU/ml) is expressed as the LH stimulation index. This is a change index calculated by computing the ratio of the post-treatment LH excretion rate divided by the baseline (pre stimulus) rate, and then taking the log (base 10) of this fraction. In this way, a decrease producing a ratio of < 1.0 gives a negative log value. Each point is plotted relative to the internal circadian time of the midpoint of the 3 h light stimulus. Zero h represents circadian midnight, defined as 3.52 h prior to the time of the aMT6s acrophase in the pre-stimulus phase assessment. The key to symbols identifies the points by age and gender of the participants, N = 98. The black line presents a 3-hour moving average of the points, with dotted lines showing 95% confidence intervals of the mean.
Figure 2
LH responses grouped by age group and times of light stimulus. The log LH response index (as described for Figure 1) is shown separately for young and older subjects versus the time of stimulus (in reference to the acrophase-peak of 6-sulfatoxymelatonin). Thick horizontal lines are medians. Blue and green boxes are interquartile ranges. The thin bars represent the range for each time bin.