Changes in hormones as well as changes to your cardiovascular, musculoskeletal and digestive systems will certainly have an impact on your daily life whether you are active or not. Active women often realize that they are pregnant when they have strange sensations during their trainings. For example, they may feel more tired in the first few minutes of training, be short of breath or have a higher than usual heart rate. They may also feel nauseous and take longer to recover from their trainings.
Active women feel the changes that are happening in their cardiovascular system within the first few days of pregnancy. Blood volume increases to supply food and oxygen to the baby and to remove excess waste from the body. The increase in blood volume occurs gradually throughout the pregnancy and by the 30e week, it is estimated to have increased by 50%. This increase also allows the body to support the loss of blood that occurs during delivery. Much of the discomfort felt during pregnancy, such as shortness of breath, can be explained by this increase. The heart beats an extra 10-15 times per minute to pump and oxygenate the additional 1.5 liters of blood and 10 to 15% more oxygen is passed through the lungs.
Your body changes daily to make space for the baby as it grows and to prepare for delivery. The extra weight, retention of water and increased laxity of your ligaments affect your center of gravity and your posture. Certain women will also feel changes in their gait, and a decreased tolerance to physical activity, to being in a seated position or instability in their joints. A hormone secreted by the placenta called relaxin allows joints and ligaments to release as well as the relaxation of the uterus, cervix and perineum to assist in the delivery of the baby on the day of delivery. While it is helpful at birth, it can exacerbate certain conditions such as: flat feet, knee hyperextension, lower back curve issues as well as back and pelvic pain.
Despite the effect of hormones on joint laxity, the risk of musculoskeletal injury is not higher in pregnant women who are active. However, caution is still important. During the third trimester in particular, when weight is highest and center of gravity has changed, pregnant women should choose physical activities that have a low risk of falls or loss of balance and ideally choose low impact activities such as brisk walking, swimming, stationary cycling, aerobics etc.