Preggo Health Nut

Pregnant and fit is not an oxymoron.. its possible!

What’s Going on with My Body??

on August 29, 2012

When you are preggo, your body goes through some serious changes… I’m sure you know about all the physical changes your body will make but, let talk about the physiological changes that are going on inside your body! These changes can really affect the way you exercise. When you are preggo, anatomic (physical) changes alter balance, flexibility, joint stability and coordination, while the physiological changes that occur affect the cardiovascular, respiratory, musculoskeletal, and gastrointestinal systems. So lets break it down! (I’ll write out all the scientific big worded explanations but… I’ll also explain in terms you can understand).

Cardiovascular changes-
Your cardiovascular system quickly jumps into overdrive in early pregnancy and stays that way until the end! Cardiac output (how many times your heart is beating and pumping out blood) increases up to 50% during pregnancy and blood volume can increase up to 45% by the 3rd trimester (Artal and Sherman 1999). Cardiac output increases primarily by an increased stroke volume (the amount of blood pumped per beat of the heart). There is also a gradual increase of the resting heart rate of 15 beats per min by the 3rd trimester. Your maximum work capacity (the max of how hard you can push yourself) is decreased dramatically by a combination of decreased cardiac reserve (because your heart is beating more and pumping more blood out at a time) and increased oxygen cost of weight bearing (since you are gradually gaining weight your body needs more oxygen pumped through it). These changes are offset to a degree by an increased capacity of the veins to reduce blood pressure and have greater vasodilation at the skin to help dissipate heat and lessen the likelihood for hyperthermia (see metabolic changes) (Artal and Sherman 1999). The concern with cardiovascular system and exercise is that the fetal blood flow will be diverted to the working muscles instead of the fetus. However, it seems that during exercise, compensatory mechanisms are in place that limit the threat of insufficient blood flow and oxygen to the fetus. You should avoid laying on your back for long periods of time after the first trimester because this compresses the vena cava causing less blood to return back to the heart.
Basically, how much blood is pumping through your body will increase; your heart will pump harder to get more blood pumping through your body to get oxygen circulated throughout quicker and your veins will dilate to accommodate the larger amount of blood flow. This will all cause your heart rate to increase faster  and beat harder when exercising, which is why taking a longer time to warm up is very important! It will help you to have a longer endurance, keep you from tiring out faster, and if you are exercising the right way it should help you to avoid having high blood pressure issues!

Respiratory changes-
The respiratory system is affected anatomically by your enlarging uterus and physiologically by hormonal influences. A resting hyperventilation occurs in pregnant women (in response to increased plasma progesterone; Araujo 1997). It takes more energy to breathe because inhalation causes the diaphragm to lower and it is resisted physically by the enlarged uterus, which it must push down during each inspiration.
Basically, your are working hard to get oxygen into your body which uses more energy.

Gastrointestinal changes-
The gastrointestinal system is affected anatomically by the enlarging uterus and physiologically by increased plasma progesterone, a smooth muscle relaxant. The combined effects of these changes contribute to constipation and a slowing of gastrointestinal mobility. The hormonal influence also promotes relaxation of the lower esophageal sphincter, which leads to increased gastric reflux or heart burn.
Basically, increased hormones will cause you to get constipated and have heart burn. (Eat lots of fiber! And have tums on hand!)

Metabolic changes-
Hyperthermia is a concern because both exercise and pregnancy increase metabolic rate and raise maternal core temperature. Core temp in excess of 102.6 degrees F (39.2 C) is potentially teratogenic (causing maldevelopment in the embryo) in the first trimester. Adaptive changes offset core temp increases and include increased minute ventilation and skin blood flow, which help augment heat dissipation and somewhat offset the potential hyperthermic effects of exercise (Artal and Sherman 1999).
Basically, your body can overheat if you push it too hard! There are adaptive changes that happen to prevent this but, still take exercise slow and steady so you don’t over heat… and drink LOTS of water! (1 oz for every 10-15 mins of exercise).

Musculoskeletal changes-
Significant changes take place in the musculoskeletal system while pregnant, and could potentially increase your risk of injury while exercising. Growth of the breasts, uterus, and fetus increase lumbar lordosis and shifts the center of gravity forward, putting strain on the low back and altering normal balance. To compound these influences, hormonal changes increase joint laxity and mobility. Relaxin and progesterone soften the ligaments surrounding the joints, and all of the joints of the body are affected. Although research has not directly linked this with an increased rate of injury, caution and moderation are appropriate (Artal and Sherman 1999).
Basically, your joints are a little more relaxed which could increase your chance of injury but if you do light resistance training and gradually build up it should improve your joint stability. But use extreme caution so you don’t pull something or seriously injury yourself!

Hope that helps to explain what’s going on inside your body! If you have any questions as always… just ask! Or if you would like me to post about something particular regarding nutrition and exercise, let me know in the comments below!


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