STUDY:Estrogen & Progesterone Beneficial To Fat Loss!?!! (preliminary results)

[BigEasy]

This is interesting, to say the least! Perhaps estrogen isn't so bad after all??? Things that make you go hmmmmm....


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Tuesday, July 2, 2002
EXERCISING at particular times in the menstrual cycle could help women to lose more weight.

That's one of the initial discoveries made by University of Adelaide PhD student Leanne Redman, who is studying the little-known impact of the menstrual cycle on women's exercise.

Early results of her research show that exercising at the later menstrual phase could burn more fat and help women to feel less tired.

"Results suggest that exercise performance is improved during the later part of the menstrual cycle-that is, when circulating concentrations of ovarian hormones (oestrogen and progesterone) are high," she says.

At the later menstrual phase, the hormones promote the use of fats as an energy source to support exercise. The use of fat in aerobic activity provides a more efficient delivery of energy, and results in fewer waste products being produced. These waste products normally contribute to fatigue.

Ms Redman's findings are of international interest to sport scientists and physicians involved in prescribing exercise programs to women for sport, fitness or health.

"According to our research, there would be clear benefits to women if their weight management programs, as well as providing a sound diet and lifestyle, took into account the physiological changes that occur during the menstrual cycle," she says.

Ms Redman is currently seeking women between the ages of 18-30

to volunteer for the last phase of her study.

This phase will look at the impact of synthetic hormones within the oral contraceptive pill on women's metabolism and exercise capacity.

The participants must be: non-smokers, already taking an oral contraceptive pill, exercise at least once a week, and from the Adelaide metropolitan area.

 

[MS]

Well it's not ground breaking news in many respects since it is well known that a) women have a higher %fat oxidation in general; b) the relative rate of fat oxidation increases in the luteal phase; and c) progesterone (which is elevated in the luteal phase) causes a significant increase in thermogenesis.

Well it makes for interesting reading. Sadly I cannot find any peer-reviewed publications from this person which means we can't really comment any more on her findings at the moment.

What I can (and will LOL) add to the discussion is some published research which concludes the opposite, with the exception of the now well known fact that women become relatively more insulin resistant in the luteal phase of their cycle (and therefore get a higher percentage of their energy from fat oxidation compared to glucose).

In this first article we find a carb meal before exercise pretty much nullifies any benefit from increased fat oxidation in the luteal phase. Perhaps this is what Redman meant by adjusting diet in the luteal to burn more fat??? However, you will find in the next two articles that there is in fact almost no difference in total calories burned between the follicular and luteal phases during exercise. Since we all know now (I hope) that the bottom line for fat loss is calories in must be less than calories out, it's hard to imagine how exercising on an empty stomach during your luteal phase will lead to a greater TOTAL calorie deficit than the equivalent exercise in the follicular phase.

Last thing to note is in the final abstract where these researchers found that exercise performance (on an empty stomach) was actually greater in women during their follicular phase!!! Go figure. All of this certainly seems in contrast to the post BigEasy has shared with us.

One last comment worth adding is that progesterone induced thermogenesis is increased in the luteal phase. Tis may have a small affect on total calories burned, all other things being equal, but in the real world, world it appears to have minimal impact on fat loss


J Appl Physiol 2002 Jul;93(1):42-50

Luteal and follicular glucose fluxes during rest and exercise in 3-h postabsorptive women.

We examined the effects of exercise intensity and menstrual cycle phase on glucose flux rates during rest and exercise in rested and fed
(3-h postabsorptive) women. Eight moderately active, eumenorrheic women were studied under conditions of rest (90 min) and
exercise (60 min, leg ergometer cycling at 45 and 65% peak oxygen consumption) during follicular and luteal phases. In both menstrual
phases, an effect of exercise intensity was evident with glucose rates of appearance and disappearance and metabolic clearance rates:
rest < 45% intensity < 65% intensity (P < 0.05). In addition, we observed no significant effect of menstrual phase on glucose rates of
appearance and disappearance and metabolic clearance rate during rest or exercise at either intensity. These results are interpreted to
mean that in women fed several hours before study 1) glucose flux is directly related to exercise intensity, 2) menstrual cycle phase
does not alter glucose flux during rest and exercise, and 3) THE SUBTLE EFFECTS OF ENDOGENOUS OVARIAN HORMONES ON GLUCOSE KINETICS ARE
SUBORDINATE TO THE MUCH LARGER EFFECTS OF EXERCISE AND RECENT CARBOHYDRATE NUTRITION.

Am J Physiol Endocrinol Metab 2002 Apr;282(4):E752-62

No effect of menstrual cycle phase on glucose kinetics and fuel oxidation during moderate-intensity exercise.

Resting and exercise fuel metabolism was assessed in three different phases of the menstrual cycle, characterized by different levels of
estrogen relative to progesterone: early follicular (EF, low estrogen and progesterone), midfollicular (MF, elevated estrogen, low
progesterone), and midluteal (ML, ELEVATED ESTROGEN AND PROGESTERONE). It was hypothesized that exercise glucose utilization and
whole body carbohydrate oxidation would decrease sequentially from the EF to the MF to the ML phase. Normal-weight healthy
females, experiencing a regular menstrual cycle, were recruited. Subjects were moderately active but not highly trained. Testing
occurred after 3 days of diet control and after an overnight fast (12-13 h). Resting (2 h) and exercise (50% maximal O(2) uptake, 90
min) measurements of whole body substrate oxidation, tracer-determined glucose flux, and substrate and hormone concentrations
were made. No significant difference was observed in whole body fuel oxidation during exercise in the three phases or in rates of glucose appearance or
disappearance. THERE WERE, HOWEVER, SIGNIFICANTLY HIGHER GLUCOSE AND INSULIN CONCENTRATIONS DURING THE FIRST 45
MIN OF EXERCISE IN THE ML PHASE vs. EF and MF phases. In conclusion, WHOLE BODY SUBSTRATE OXIDATION AND GLUCOSE UTILIZATION DID NOT
VARY SIGNIFICANTLY ACROSS THE MENSTRUAL CYCLE IN MODERATELY ACTIVE WOMEN, EITHER AT REST OR DURING 90 MIN OF MODERATE-INTENSITY EXERCISE.
During the ML phase, however, this similar pattern of substrate utilization was associated with greater glucose and insulin
concentrations. (MY NOTE-THIS IS INSULIN RESISTANCE!!!) Both estrogen and progesterone are elevated during the ML phase of the menstrual cycle, suggesting that one or both
of these sex steroids may play a role in this response.

Am J Physiol Endocrinol Metab 2001 Oct;281(4):E817-25

Glucose kinetics and exercise performance during phases of the menstrual cycle: effect of glucose
ingestion.

To study the effect of menstrual cycle phase and carbohydrate ingestion on glucose kinetics and exercise performance, eight healthy,
moderately trained, eumenorrheic women cycled at 70% of peak O(2) consumption for 2 h and then performed a 4 kJ/kg body wt
time trial. A control (C) and a glucose ingestion (G) trial were completed during the follicular (F) and luteal (L) phases of the menstrual
cycle. Plasma substrate concentrations were similar before the commencement of exercise. Glucose rates of appearance and
disappearance were higher (P < 0.05) during the 2nd h of exercise in FC than in LC. The percent contribution of carbohydrate to total
energy expenditure was greater in FC than in LC, and SUBJECTS PERFORMED BETTER (13%, P < 0.05) IN FC. Performance improved
(19% and 26% in FG and LG compared with FC and LC, respectively, P < 0.05) with the ingestion of glucose throughout exercise.
THESE DATA DEMONSTRATE THAT SUBSTRATE METABOLISM AND EXERCISE PERFORMANCE ARE INFLUENCED BY THE MENSTRUAL CYCLE PHASE, BUT INGESTION
OF GLUCOSE MINIMIZES THESE EFFECTS.

 

[BigEasy]

MS,
There is no peer review on this because the study is actually ongoing. Prelims were given on this phase which is part of a larger study involving oral contraceptives and fitness. I believe the lady is/was a doctoral candidate and this was part of her thesis.

Anyway, anyone in NZ that wants to participate in the study can look here for more info. http://www.adelaide.edu.au/pr/publications/inside_adelaide/2002/13may/news/women.html

Just goes to show us all that the physiology and hormonal interactions are not so well understood that there isn't much room for contradiction and refinment.

 

[MS]

"Just goes to show us all that the physiology and hormonal interactions are not so well understood that there isn't much room for contradiction and refinment."

Amen. I was not really debating the preliminary results, and I fully understand that it can take a long time from preliminary results to publication. I was merely commenting that it's an interesting finding because it DOES contrast with other research. I look forward to reading the whole story one day.

FYI, Adelaide is in Australia, not NZ

 

[macrophage69alpha]

progesterone has been shown in some studies to be thermogenic and perhaps lipolytic... it should be noted that some of the weight gain associated with the pill is likely due to PROGESTIN replacement

ESTROGEN... on the other hand plays little or no role in lipolysis (other than to reduce circulating thyroid and inhibit lipolysis through A2 binding and upregulation).. estrogen may have some beneficial effects on insulin sensitivity..


note- increased progesterone should = increased serotonin which may also be beneficial (less comfort eating)

 

[wilson6]

"Results suggest that exercise performance is improved during the later part of the menstrual cycle-that is, when circulating concentrations of ovarian hormones (oestrogen and progesterone) are high," she says.

"At the later menstrual phase, the hormones promote the use of fats as an energy source to support exercise. The use of fat in aerobic activity provides a more efficient delivery of energy, and results in fewer waste products being produced. These waste products normally contribute to fatigue. "


Campbell et al., 2001 found just the opposite. Performance decreased in the luteal phase, but CHO ingestion negated that response. While fat oxidation is increased in the luteal phase, it is as MS said, likely due to insulin resistance; there are potentially negative effects of P on GLUT-4. Regardless, this negative effect on performance can be overcome by CHO ingestion during exercise.

It should be noted that exercise intensity beyond 65% VO2max increases the reliance upon CHO, not fat. In fact, fat oxidation decreases as exercise intensity increases beyond 65% VO2max. Thus, the contention that exercise during LP would enhance performance doesn't make sense unless intensity is low, but competitive athletes do not perform at a low exercise intensity. The only way to increase fat oxidation at higher exercise intensity is with an intralipid/heparin infusion, but even then the effects of decreasing intramuscular pH at greater exercise intensity limit the transport of FFAs by CPT-1. Thus, at higher exercise intensities, limiting CHO Ra, Rd and oxidation would impair performance, not enhance it regardless of what is happening with FFA Ra.

In men, several days of estrogen administration reduces glucose Ra, but doesn’t change substrate utilization which is in contrast to the effects of E in male rats where E enhances fat oxidation.

Overall, gender effects on substrate metabolism are more dependent on exercise intensity, level of training and diet than menstrual phase, and while gender and phase effects have been shown, they usually occur at lower levels of exercise intensity (less than 60%) and in untrained or low to moderately trained subjects. Romijn et al., 2000 found no differences between highly trained men and women with exercise intensity at or above 65% but their n was relatively low and they didn’t control for phase.

Progesterone increases appetite thus leading to weight gain, that's why early research focused on the use of Megace to increase body mass in HIV patients, but it only made them fat, unlike AAS that increase appetite and partitions food toward lean mass.

19-nor derived progestagens may also increase water retention.

Estrogen appears to reduce appetite at least in animal studies. When female rats are ovariectomized, they eat more and gain weight; when given estrogen replacement, they eat less and lose the weight. I’ve also found that clients who have undergone ovarian failure as a function of short-term chemo for breast cancer and are not on any hormone replacement of other meds such as Tamoxifen, their appetite following the decrease in circulating E increases dramatically and they gain weight (20 – 30 lbs) like the rats. My guess is that E and/or P may regulate leptin sensitivity in the brain and consequently appetite. Androgens on the other hand reset the fat mass/leptin concentration ratio (i.e., for the same amount of fat there is less circulating leptin). Androgens then may increase leptin sensitivity, perhaps peripherally and/or may decrease myostatin express that in turn regulates leptin concentration and likely sensitivity.

Bottom line, if I were a natural female athlete, I'd be on a very low dose OC to suppress my own E and P production and maintain chronic low levels of E and P.

James et al., found no differences in glycogen depletion/loading between men and women who were on the pill. In addition, the pill maintained their E and P levels at early follicular phase levels and that is just where I'd want them all the time.

Having said all of that, if you’re a female and juiced, then it is a whole different, not well-understood and complicate metabolic situation.

W6

 

[MS]

I agree wholeheartedly with your synopsis Wilson6, but I'm guessing that either this researcher has some serious methodological problems, or that she is (quite likely) dealing with ordinary women exercising at a low-moderate intensity on an empty stomach. After all, the only exercise inclusion criteria is that they exercise once a week (and I'll bet that's NOT weight training!). I still can't fathom how this would help women lose fat unless, as you say, you're going to suppress a women's natural gonadal steroid fluctuations with replacement therapy. But I can't believe that HIGH E and P (as implied in that article) would be the replacement goal!!!!! Of course the other possibility is that the reporter totally screwed up the story. I am inclined to believe this since they got the researchers name completely wrong. It should have been Roberts rather than Redman! And I have yet to see a lay reporter get a science story completely correct.