Exercise during pregnancy
Research suggests that in the absence of medical or obstetric complications, exercise should be encouraged and participated in throughout pregnancy. As long as the exercise is safe and appropriate, studies have shown that there are minimal risks associated. In fact, being inactive can actually increase risk of developing health problems during pregnancy.  

How is exercise beneficial?
Exercise during pregnancy has proven benefits to both the mother and the baby, as long as these exercises are appropriate to each stage of pregnancy.
These benefits include:

• Reduces the risk of gestational obesity, diabetes and other associated complications
• Enhances mental well-being, body image and self-esteem
• Helps to prevent and reduce musculoskeletal conditions such as pelvic and back pain
• Lowers the risk of pregnancy-related high blood pressure and pre-eclampsia
• Helps to maintain cardiovascular fitness and physical conditioning that may be required for labour and caregiving following pregnancy

Exercising throughout pregnancy
In general, if you feel well and have been exercising consistently prior to pregnancy it is safe to continue with this during the first trimester. This means that even if you have been exercising at high intensities it is safe to continue to do so. However, if you have not been exercising prior to pregnancy it is recommended that you commence at low intensities.

Once the pregnancy progresses to the second and third trimester, there are changes that need to be made to ensure continued safety with exercise. It is recommended to engage in light resistance and aerobic exercise, as the evidence suggests that at these intensities there is no negative effects on risk of pre-term labour, mode of delivery, newborn health, or gestational age.

Changes to exercise prescription
The following changes should be made to exercise prescription during the second and third trimester of pregnancy.

1. Extra caution needs to be given to explosive / ballistic type movements. With pregnancy the laxity of joints increases due to the release of specific hormones such as Relaxin, placing individuals at a greater risk of overextending joints.  
2. Exercises that are completed on your back or lying down need to be avoided after 16 weeks. This is because increased weight from the baby can temporarily put increased pressure on the vena cava which returns the deoxygenated blood from the body back to the heart. Increased pressure on the vena cava can result in feelings of dizziness and breathlessness.
3. Abdominal exercises should be avoided if abdominal separation occurs (which is referred to as diastasis recti). Diastasis recti can also be exacerbated by poor form and lifting heavy weights as this places increased pressure around the abdominal region.
4. Thermoregulation is harder to achieve during pregnancy so extra consideration should be given to the location of exercise, the clothing that you wear, and it should be ensured that hydration is adequate.
5. Exercises should be avoided that increases the risk of falls or physical injury, including jumping, contact sport, horse riding or scuba diving.

Signs and symptoms that mean you should stop exercising
It is recommended to seek advice from your doctor or midwife in the event of the following

• Muscle weakness
• Shortness of breath, feeling faint, dizziness or headaches
• Vaginal bleeding or fluid loss
• Pain that presents in the lower back, pelvic/pubic area or abdomen as this may potentially indicate preterm labour
• Dizziness or breathlessness.

The bottom line
Exercising is safe to participate in during pregnancy and should be encouraged. However, specific changes and modifications should be made to exercise during the second and third trimester of pregnancy to avoid any concerns or complications. Not sure how to get started or where to get help from? Consult your nearest Accredited Exercise Physiologist today.

Written by Rebecca Dostan - AEP, AES, ESSAM

 References  
Brown, WJ, Hayman, M, Haakstad, LAH, Lamerton, T, Mena, GP, Green, A, Keating, SE, Gomes, GAO, Coombes, JS, Mielke, GI 2022, ‘Australian Guidelines for physical activity in pregnancy and postpartum’, Journal of Science and Medicine in Sport, vol. 25, no. 6, pp 511-519.  

Dillard, DM 2016, ‘Exercise and pregnancy’, The International Journal of Childbirth Education, vol. 31, no. 1, pp. 8-.

Exercise is Medicine 2019, Being active during pregnancy, viewed 8 Octoboer 2024, < https://www.exerciseismedicine.org/assets/page_documents/EIM_Rx%20for%20Health_Pregnancy.pdf>.

Exercise is Medicine 2024, Pregnancy and exercise, Exercise is Medicine, viewed 9 Octover 2024, <http://exerciseismedicine.com.au/wp-content/uploads/2018/06/2014-Pregnancy-FULL.pdf>.
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Santos-Rocha, R (ed.) 2022, Exercise and physical activity during pregnancy and postpartum : evidence-based guidelines, 2nd ed., Springer, Cham, Switzerland.

Physical health

When a sedentary person becomes more active, substantial changes occur to their body. The extent of these adaptations or changes is determined by the amount of aerobic exercise and physical activity that is undertaken. This means the greater the volume and intensity of aerobic exercise that is participated in, the greater the changes that will occur to the body. The below changes occur to different parts and systems of the body.
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Improvement in cardiovascular and respiratory function

• Increased oxygen uptake
• Decreased volume of air required for energy production at a given intensity
• Decreased heart rate and blood pressure at a given intensity
• Increased capillary density in muscle, resulting in increased ability to transfer oxygen to the corresponding site.
• Increased exercise threshold for the onset of disease specific signs or symptoms (e.g angina, ischemic ST-segment depression, claudication)

Reduction in cardiovascular disease risk factors

• Reduced blood pressure
• Increased high density lipoprotein (good cholesterol) and decreased triglyceride levels
• Reduced total body fat and intraabdominal fat (visceral fat)
• Reduced insulin needs, and improved blood glucose tolerance
• Reduced body inflammation

Decreased morbidity and mortality.

• Reduced rates of death from coronary artery disease
• Reduced rates of coronary vascular disease, coronary artery disease, stroke, T2DM, metabolic syndrome, osteoporotic fracture, cancer and gallbladder disease
• Overall reduced risk of developing chronic health conditions 

Mental health

As physical and mental health are generally interconnected and linked, improvements in physical health can intern result in improvements in mental health. Therefore, increasing physical health and consequently mental health by participating in aerobic exercise can result in:
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• Increased self-esteem
• Increased exercise self-efficacy
• Improved body image
• Improved physical quality of life
• Increased likelihood of sustained physical activity over the long term
• Reduced anxiety and depression

The impact of exercise on mood is one of the most widely studied mechanisms linking exercise to mental health, both through acutely enhancing mood and by improving emotional regulation during stressful life circumstances. People participating in regular exercise, even for short periods of time, are less likely to experience symptoms of depression and current research suggests that as little as 1-hour may be enough to prevent future depressive episodes. Exercise has also been shown to have a protective effect against future incidents of anxiety. That is, a small but statistically significant effect has been found on reducing anxiety symptoms and severity when and individual is participating in aerobic exercise. 

General wellbeing
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Evidently, aerobic exercise offers numerous health benefits, including improved cardiovascular health, better mental health, and enhanced overall well-being. Enhanced overall well-being can include, but is not limited to

• Improved cognitive function
• Enhanced physical function and independent living in older adults
• Enhanced quality of life
• Improved sleep quality, duration and efficiency
• Enhanced performance within work, recreational and sporting activities
• Reduced risk of falls and injuries from falls that might occur within older adults
• Weight management 

​Aerobic exercise recommendations
Given the wide variety of health benefits participating in regular aerobic exercise has to offer, there are evidence-based recommendations around how much aerobic exercise an adult should be participating within each week. These recommendations can be viewed below. 

Frequency

• Adults should be active most days, preferably every day.

Intensity

• Moderate to vigorous

Time

• 2.5 to 5 hours of moderate intensity physical activity
• 1.25 to 2.5 hours of vigorous intensity physical activity
• Or a combination of both

Type

• Walking, jogging, hiking, rowing, bike riding, x-training, swimming, spin bike riding

Need help or not sure how to get started?
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Accredited Exercise Physiologist are well-positioned to support people in the commencement and continuation of exercise. They have specialised training in the design and delivery of exercise and lifestyle interventions for people with chronic health conditions and complex needs. At Optimum Exercise Physiology we offer a wide range of options to suit an individual’s needs, which include 1:1 exercise sessions, group exercise sessions and independent exercise sessions. If you would like more information on the services we have to offer, click on the link below.  

​Group Classes - OPTIMUM EXERCISE PHYSIOLOGY (optimumep.com.au)

References

• Wilmore, JH & Knuttgen, HG 2003, ‘Aerobic Exercise and Endurance: Improving Fitness for Health Benefits’, The Physician and Sportsmedicine, vol. 31, no. 5, pp. 45–51.
• Smith, PJ & Merwin, RM 2021, ‘The Role of Exercise in Management of Mental Health Disorders: An Integrative Review’, Annual Review of Medicine, vol. 72, no. 1, pp. 45–62.
• Nogueira de Souza, PV, Olegario, RL, Lima de Araujio Riberio, A 2020, ‘Aerobic Exercise and Health Benefits’, Journal of Physical Fitness, Medicine & Treatment in Sports, vol. 7, no. 4, pp. 1–2.
• Exercise is Medicine 2024, Depression & Exercise, Exercise is Medicine, viewed 21 September 2024, <EIM-FactSheet_Depression_Professional-2020.pdf (secureserver.net)>.
• Exercise is Medicine 2024, Anxiety & Exercise, Exercise is Medicine, viewed 23 September 2024, <EIM-FactSheet_Anxiety_Prof_2022.pdf (secureserver.net)>.
• Australian Government 2024, Physical activity and exercise guidelines for all Australians: For adults (18 to 64 years), viewed September 25 2024, <For adults (18 to 64 years) | Australian Government Department of Health and Aged Care>
  

Written by Bec Dostan - AEP, AES, ESSAM