2. INTRODUCTION
During endurance exercise, fuel source and utilization plays
a primary role in performance.
The contribution and expenditure of fat and carbohydrates
for the synthesis of ATP during exercise is regulated by
several factors, including:
Duration of exercise,
Intensity of work,
A person's age,
Training status,
Diet and gender.
3. INTRODUCTION
Before puberty, there is no difference between males
and females when it comes to substrate usage during
exercise
women are known to rely more on fat than men for
the same relative intensity of exercise.
physiological characteristics in metabolism, energy
expenditure and hormonal influences on women
during exercise follow the releases of sex hormones.
4. ALTERING CELL FUNCTION
THROUGH FEEDBACK CIRCUITS
Two major female sex hormones, estrogen and
progesterone play an essential role in a women's
reproductive system.
Estrogen and progesterone, which are derived from
cholesterol, are often referred to as ovarian hormones
since they are produced and secreted primarily by the
ovaries.
5. ALTERING CELL FUNCTION
THROUGH FEEDBACK CIRCUITS
The rate and amount of carbohydrate (via
glucose and glycogen) during rest and exercise
is primarily determined by the energy needs of
the muscle.
Blood glucose and muscle glycogen are
essential for vigorous and prolonged strenuous
exercise.
Exhaustion during exercise is highly influenced
by the development of hypoglycemia (low blood
6. ALTERING CELL FUNCTION
THROUGH FEEDBACK CIRCUITS
In respect to female utilization of glucose and
glycogen during endurance exercise, the
consensus in the research suggests there is a
lower glucose appearance and slower rate of
glucose disappearance in women, as compared
with men during endurance exercise
7. ENERGY REGULATION, HORMONAL
INFLUENCES AND FAT METABOLISM
Tarnopolosky (2008) notes that most studies show
that females store slightly higher levels of
intramuscular fat, which is stored in small lipid
droplets in muscle.
Tarnopolosky continues that women have more lipid
droplets as opposed to larger lipid storage depots.
During moderately vigorous exercise that is
sustainable for 90 minutes or longer (approximately
55% to 75% VO2max) there is a progressive decline in
muscle glycogen usage and greater reliance on fat
oxidation (breakdown) for ATP synthesis (Holloszy et
8. ENERGY REGULATION, HORMONAL
INFLUENCES AND FAT METABOLISM
This adaptation during endurance exercise is often
referred to as glycogen sparing.
Most research indicates that total body lipolysis (fat
breakdown) is higher in women than in men, as
glycerol (the backbone molecule of triglycerides) is
elevated as compared to men during endurance
exercise (Tarnopolosky, 2008; D'Eon and Braun,
2002).
9. ENERGY REGULATION, HORMONAL
INFLUENCES AND FAT METABOLISM
Current investigations indicate that women use more
fat and less carbohydrate to fuel exercise at any given
submaximal intensity due to estradiol (Tarnopolosky).
Tarnopolosky adds that current findings indicate
women are not as efficient in carbohydrate-loading
protocols that result in supercompensation of
glycogen storage.
It is a direct result of higher levels of estradiol
(Tarnopolosky). This factor may slightly compromise
performance during marathon and ultra marathon-like
events in females.
10. MENSTRUAL CYCLE EFFECT
EXERCISE METABOLISMThe ovarian hormones, estrogen and progesterone
fluctuate during the menstrual cycle, ) with inferences
for exercise performance(Oosthuyse and Bosch, 2010)
Estrogen alters fat, carbohydrate and protein
metabolism, favorably affecting performance whereas
progesterone appears to act in opposition (to
estrogen).
The researchers propose that increases in estrogen
enhance glucose appearance and utilization by the
slow-oxidative type I muscles fibers.
The high estrogen content during the luteal phase
augments glycogen storage, which additionally has a
11. FEMALE HORMONAL RESPONSE TO
RESISTANCE TRAINING
Women who are deficient in estrogen tend to have a
negative impact in bone turn-over markers and bone
mineral density (Moghadasi and Stravaspour, 2012).
The implementation of a resistance training program
may help increase the hormones of bone formation,
especially in women of reproductive age.
Women who are postmenopausal have a decrease in
estrogen levels, which can lead to negative effects on
bone mass (Moghadasi and Stravaspour, 2012).
