strate utilization, serum lactate levels, oxygen
uptake, cardiac function or anaerobic threshold
during submaximal exercise or serum lactate
levels and oxygen uptake during maximal exer-
cise. Additionally, there was no effect on time to
exhaustion on a cycle ergometer in two studies
(Williams 1999).
safety
Bucci (1993) indicates that the long-term safety
of CoQ 10 has been thoroughly documented,
although others indicate that it may actually
serve as a pro-oxidant and generate free radicals
(Demopoulouset al. 1986). In a recent study,
Malm and others (1996) reported evidence of
muscle tissue damage in exercising subjects who
were supplemented with 120 mg CoQ 10 · day–1
for 20 days.
Choline
theory
Choline, a non-essential nutrient, is an amine
widely distributed in foods and may also be syn-
thesized in the body. Its primary metabolic role
in humans is to serve as a precursor for the
formation of phosphatidylcholine (lecithin) and
other essential components of cell membranes
and for the formation of acetylcholine, the neuro-
transmitter at the myoneural junction that
initiates electrical events in muscle contraction.
Conlay et al. (1992) reported significantly
lower plasma choline levels following a 42.2-km
marathon, suggestive as an aetiologic factor in
the development of fatigue because of the possi-
bility of decreased acetylcholine production
and resultant impaired muscular contractility.
Theoretically, choline supplementation will
enhance acetylcholine synthesis and prevent
acetylcholine depletion and subsequent fatigue
in endurance events.
efficacy
Von Allwörden et al. (1993) noted that lecithin
362 nutrition and exercise
supplementation helped prevent a decrease
in serum choline in triathletes and adolescent
runners following long-term hard physical
stress, but they did not evaluate the effects on
performance. No studies of choline supplemen-
tation and physical performance were presented
in a recent review (Kanter & Williams 1995). Sub-
sequent to this review, a double-blind, placebo-
controlled, crossover study with trained male
cyclists, using a single dosage of 2.43 g choline
bitartrate, reported that although there was a sig-
nificant increase in serum choline, compared
with the placebo there were no significant effects
on time to exhaustion in either a high intensity
(150%V.
o2max.) or a prolonged (70% V.
o2max.) cycle
exercise test (Spector et al. 1995). At the present
time, there are no data to support choline supple-
mentation as an effective ergogenic, but confirm-
ing research is desirable.safety
Choline is a natural dietary component and
small supplemental doses are not considered
unsafe.Inosinetheory
Inosine, a non-essential nutrient, is a nucleoside.
Somein vitroresearch has led to the theory that
inosine supplementation increases the amount
of 2,3-DPG in the red blood cell. Theoretically,
increased levels of 2,3-DPG may facilitate the
release of oxygen from the red blood cells to the
muscle and enhance aerobic endurance exercise.efficacy
Only two well-controlled studies have evaluated
the purported ergogenic effect of inosine supple-
mentation. Two days of inosine supplementation
(6000 mg · day–1) exerted no significant effect on
heart rate, ventilation, oxygen consumption, or
lactic acid production in highly trained runners
during both submaximal and maximal exercise,