Encyclopedia of

272 Ginseng, Asian (Panax ginseng)
The detrimental effects of night shifts were clearly
seen. A constant trend in favor of ginseng compared
to placebo was noted. Ginseng ratings were favorable
for mood criteria, but not for physical well-being
symptoms. Ginseng restored blood glucose levels
raised by night shift stress. A small but consistent
antifatigue activity of ginseng was concluded. [27]
Various tests of psychomotor performance were
carried out in a cohort of 16 healthy male volunteers
given a standardized ginseng extract (100 mg ginseng
extract twice a day for 12 weeks) and in a similar group
given placebo under double-blind conditions. A favorable
effect of ginseng relative to baseline performance
was observed in attention (cancelation test), processing
(mental arithmetic, logical deduction), integrated
sensory-motor function (choice reaction time), and
auditory reaction time. However, end performance of
the ginseng cohort was only statistically superior
(p < 0.05) to the placebo group in mental arithmetic.
No difference between ginseng and placebo was found
in tests of pure motor function (tapping test), recognition
(digit symbol substitution), and visual reaction
time. [28]
In a double-blind, placebo-controlled, crossover
study, 43 top triathletes received either placebo or
200 mg of a standardized ginseng extract per day for
periods of 10 weeks, respectively. Significant differences
(p < 0.05) in various endurance parameters
were only seen after the second treatment phase. It
was concluded that ginseng improves endurance (resistance
against end of season stress), but not optimum
performance. [29]
Twenty top class male athletes received 200 mg
standardized ginseng extract per day for 9 weeks. In
the bicycle ergometer exercise test lasting 8 min, the
post-treatment values were higher for maximal oxygen
absorption and lower for blood lactate level and heart
rate during exercise compared to pretreatment values.
The differences were significant (p < 0.001). [30]
A double-blind study involved 30 athletes who
received daily either placebo (n ¼ 10), 200 mg ginseng
extract standardized to 7% ginsenosides (n ¼ 10), or
400 mg vitamin E and 200 mg ginseng extract standardized
to 4% ginsenosides (n ¼ 10) for 9 weeks.
The same bicycle ergometer test was used and statistically
significant variations in heart rate (p < 0.05),
blood lactate (p < 0.01), and maximal oxygen
absorption (p < 0.01) after exercise between either
of the two ginseng preparations and placebo were
found. Differences between the two ginseng preparations
were not statistically significant. The levels of testosterone
and luteinizing hormone in plasma, and free
cortisol in urine, were unchanged after all treatment
periods. [31]
A further double-blind, placebo-controlled study
with 28 top class male athletes examined the persistence
of the effects of 9 weeks’ treatment (placebo or
200 mg ginseng extract with 4% ginsenosides) beyond
the treatment period. Ginseng resulted in a significant
improvement of maximal oxygen uptake during
exercise (p < 0.01), heart rate at maximal exercise
(p < 0.001), forced expiratory volume (p < 0.01),
forced vital lung capacity (p < 0.05), and visual reaction
time (p < 0.01) compared with placebo. These
positive effects lasted for at least 3 weeks after treatment,
and it was concluded that the effects of ginseng
are based on clinically relevant metabolic changes
that persist for a certain period after treatment. [32]
In a double-blind, placebo-controlled study with 50
ambulatory patients suffering from asthenia, depressive
syndrome, or neurovegetative disorders, the effects
of 8 weeks’ treatment with 200 mg=day of a standardized
ginseng extract on performance in two psychometric
tests and on results from a comprehensive
psychological questionnaire (Sandoz Clinical Assessment
Geriatric) were studied. Significant improvement
(p < 0.05 and p < 0.01) was seen in most of the
parameters. [33]
In a randomized double-blind study, 31 healthy
male volunteers received 200 or 400 mg ginseng extract
per day for 8 weeks. Ginseng had no effect on oxygen
consumption, respiratory exchange ratio, minute ventilation,
blood lactic acid concentration, heart rate, and
perceived exertion. [34]
In another randomized double-blind study, 19
healthy female volunteers received daily 200 mg
ginseng extract or placebo for 8 weeks. It had no effect
on maximal work performance and resting, exercise,
recovery oxygen uptake, respiratory exchange ratio,
minute ventilation, heart rate, and blood lactic acid
levels. [35]
In a double-blind, placebo-controlled, crossover
study in 8 healthy volunteers (mean age 25 yr) who
regularly practised physical activities, 30 days of daily
oral treatment with 400 mg of a standardized ginseng
extract did not improve performance at supramaximal
exercise (125% of the maximum aerobic power on
bicycle ergometer), nor did it influence blood lactate
or blood testosterone. [36]
In a study on blood oxygenation status of 8 male
and 2 female middle aged subjects (average 50 yr
old), a significant (p < 0.05) increase of resting arterial
pO2 was found after 4 weeks’ oral treatment with
200 mg standardized ginseng root extract per day.
The resting arterial pO 2 was increased by 4.5 mmHg.
In synergy with oxygen treatment, the increase was
10.1 mmHg. Venous pO2 was decreased (4.3 mmHg). [37]
The effects of 400 mg=day of a ginseng extract on a
variety of cognitive functions were compared with
placebo in a double-blind, randomized study in which
112 healthy volunteers older than 40 yr (55 on ginseng,
57 on placebo) were treated for 8–9 weeks. The ginseng