Blood T measures can vary quite a bit from day to day or even from hour to hour. What factors influence this measure and to what degree?
Some examples are:
--Time of measure--
T levels are usually quite a bit higher in the morning than the evening. ~30% sounds familiar. I would have to search on the Internet to get more reliable numbers.
--AS or HRT--
Obvoiusly testosterone based compouds can influence the measurement. The significance and timing depends on what type of AS or HRT is used and the amount.
--Diet--
Fasting can reduce T levels. I believe some athletes go on fasts to hide T levels. I recall Incluedon (spelling) saying something about a 50% decrease in T levels after a multiple day fast. Would shorter fasts have a significant effect or a cutting diet?
The study at http://jap.physiology.org/cgi/content/full/82/1/49 and article at http://www.thinkmuscle.com/articles/incledon/diet-01.htm give a good summary on how diet effects testosterone level. The first study found the following correlations between dietary nutrients, listed highest to lowest:
MUFA, g 1,000 kcal1 day1 ______ 0.79
SFA, g 1,000 kcal1 day1 _______ 0.77
Fat, % ________________________ 0.72*
Cholesterol, mg 1,000 kcal1 day1_ 0.53
PUFA, g 1,000 kcal1 day1 ______ 0.25
Protein/fat _____________________ 0.16
CHO/fat _______________________ 0.16
Energy, kJ ____________________ -0.18
Dietary fiber, g 1,000 kcal1 day1 -0.19
CHO, % _______________________ -0.30
Protein/CHO ___________________ -0.59
PUFA/SFA _____________________ -0.63
Protein, % ____________________ -0.71*
I would like to know how long it takes for these dietary changes to show up on a blood test. Would the previous meal make a signifcant difference? Would one have to go on such a diet for days to see changes?
--Workouts--
There is often a transient boost in T after a workout. Overtraining can decrease T levels.
--Body Composition--
Having a BF that is quite a bit off from your set point can significantly alter T levels. For example T levels are likely to decrease when BF gets very low.
What else can be added?
Some examples are:
--Time of measure--
T levels are usually quite a bit higher in the morning than the evening. ~30% sounds familiar. I would have to search on the Internet to get more reliable numbers.
--AS or HRT--
Obvoiusly testosterone based compouds can influence the measurement. The significance and timing depends on what type of AS or HRT is used and the amount.
--Diet--
Fasting can reduce T levels. I believe some athletes go on fasts to hide T levels. I recall Incluedon (spelling) saying something about a 50% decrease in T levels after a multiple day fast. Would shorter fasts have a significant effect or a cutting diet?
The study at http://jap.physiology.org/cgi/content/full/82/1/49 and article at http://www.thinkmuscle.com/articles/incledon/diet-01.htm give a good summary on how diet effects testosterone level. The first study found the following correlations between dietary nutrients, listed highest to lowest:
MUFA, g 1,000 kcal1 day1 ______ 0.79
SFA, g 1,000 kcal1 day1 _______ 0.77
Fat, % ________________________ 0.72*
Cholesterol, mg 1,000 kcal1 day1_ 0.53
PUFA, g 1,000 kcal1 day1 ______ 0.25
Protein/fat _____________________ 0.16
CHO/fat _______________________ 0.16
Energy, kJ ____________________ -0.18
Dietary fiber, g 1,000 kcal1 day1 -0.19
CHO, % _______________________ -0.30
Protein/CHO ___________________ -0.59
PUFA/SFA _____________________ -0.63
Protein, % ____________________ -0.71*
I would like to know how long it takes for these dietary changes to show up on a blood test. Would the previous meal make a signifcant difference? Would one have to go on such a diet for days to see changes?
--Workouts--
There is often a transient boost in T after a workout. Overtraining can decrease T levels.
--Body Composition--
Having a BF that is quite a bit off from your set point can significantly alter T levels. For example T levels are likely to decrease when BF gets very low.
What else can be added?
