From the fifth week of gestation, there is a
significant alteration to the cardiovascular system
as blood flow must be shifted to the foetus
changes structurally, with the internal cavity
increasing in size with no commensurate
increase in wall thickness. Resting heart
rate increases by 15 to 20bpm, and stroke
volume (the volume of blood pumped
from the left ventricle per beat) increases
by approximately 10 per cent in the first
trimester.
Thermoregulatory adaptations to
pregnancy: The foetal neural tube is
developed at around five to six weeks from
the last menstrual period: raising body
core temperature above 39°C can increase
the risk of foetal (neural tube defect)
abnormalities.
Exercise at altitude: Given the
popularity of altitude training centres here in
Australia, we felt it was important to include
this information in this review. The theoretical
concern with exercise at altitude (the
authors admit there are no studies available
on pregnant endurance athletes exercising
at high altitude, simulated or actual) is that,
while pregnant, hypoxia and exercise both
decrease blood flow to the uterus, which
would result in a decrease in foetal oxygen
saturation. The authors therefore advise
avoiding high-intensity exercise at altitudes
greater than 1,500 to 2,000 metres.
Endurance: In recreational athletes there
were no differences in maximal aerobic
capacity (VO2max), however in highly
conditioned athletes a moderate to high
level of exercise during and after pregnancy
may lead to an increase in VO2max of 5 to
10 per cent.
Strength training: Light to moderate
weight training was reported to generally
have no adverse health effects; however,
there is scant research available on strenuous
strength training in recreational individuals
and none on pregnant elite athletes.
Sports and activities to avoid: Sports or
activities associated with possible trauma by a
collision, or being hit by something (ball, stick,
falling) should be avoided. Similarly, sudden
decelerations are highlighted (e.g. bobsleigh)
and similar concerns would apply to sports
with inertial effects (e.g. Olympic Lifts). Also,
pregnant women are advised not to scuba
dive, as the foetus is not protected from
decompression problems and is therefore at
risk of malformation and gas embolism.
Fatigue: This is a common complaint
throughout
pregnancy,
affecting
approximately 90 per cent of women. It
is generally not related to a pathological
problem; however, exercising women are
advised to get their haemoglobin checked to
ensure they are not anaemic.
Gestational weight gain: This is the
amount of weight gained from conception
to delivery. The authors have provided
guidelines, which are based upon their prepregnancy BMI (see Table 2 in the full article).
For example, a normal weight woman (BMI
18.5 to 24.9kg/m2) should have a weekly
weight gain of 0.35 to 0.5kg. Women with
twins have a separate recommendation,
for example a normal BMI woman would
gain 16.8 to 24.5kg during the course of her
pregnancy with twins.
Conclusions: This is a comprehensive
guideline, a must-read for all active pregnant
women, women planning a pregnancy, AEPs
and personal trainers.
Pros: Good article which summarises
common
conditions,
illnesses
and
complaints that may interfere with strenuous
exercise and provides recommendations for
exercise training. We strongly recommend
all women who are pregnant or planning
to get pregnant seek their GP’s and/or
specialist’s advice with regard to physical
activity/exercise.
Given this article is available free online,
we advise all women who are pregnant or
planning to get pregnant to read this article.
Cons: None.
Associate Professor Mike Climstein, PhD FASMF
FACSM FAAESS is one of Australia’s leading
Accredited Exercise Physiologists and researchers.
[email protected]
Joe Walsh, MSc is a sport and exercise scientist.
As well as working for Charles Darwin and Bond
Universities, he is a director of Fitness Clinic in Five
Dock, Sydney. fitnessclinic.com.au
NETWORK SUMMER 2016 | 59