Pre-pregnancy obesity is a risk factor for preeclampsia, gestational diabetes, and hypertension. Regular exercise during pregnancy has been shown to decrease the risk of these obstetrical complications. The purpose of this prospective study was to measure the effects of an exercise program in normal-weight and overweight/obese pregnant women on blood pressure (BP) and cardiac autonomic function, determined by heart rate variability (HRV) and baroreflex sensitivity (BRS). Twenty-two sedentary pregnant women, recruited at 20 weeks gestational age (GA), were grouped as normal weight or overweight/obese. They were systematically assigned to an exercise (walking) group or control (nonwalking) group after the first participants were randomly assigned. Women in the walking groups participated in a 16-week, low-intensity walking program. BP, HRV, and BRS were measured at rest and during exercise at the beginning (20 weeks GA) and end (36 weeks GA) of the walking program. Results indicated that women in the control groups (especially overweight women) showed changes in BP, HRV, and BRS over pregnancy that were not seen in the walking group. Overweight women in the control group increased resting systolic BP by 10 mmHg and diastolic BP by 7 mmHg. HRV declined in the control group but not in the walking group. A reduction in BRS and R-R interval at rest was found in all groups except the walking normal-weight group. The results suggest that an exercise program could attenuate the increase in BP and the loss of parasympathetic tone associated with pregnancy, especially in overweight women.
Akselrod, S., Gordon, D., Madwed, J.B.Snidman, N.C., Shannon, D.C., & Cohen, R.J. ( 1985). Hemodynamic regulation: Investigation by spectral analysis . American Journal of Physiology, 249, H867-H875.
2.
Akselrod, S., Gordon, D., Ubel, F.A., Shannon, D.C., Berger, A.C., & Cohen, R.J. ( 1981). Power spectrum analysis of heart rate fluctuation: A quantitative probe of beat-to-beat cardiovascular control. Science, 213, 220-222.
3.
Amano, M., Kanda, T., Ue, H., & Moritani, T. ( 2001). Exercise training and autonomic nervous system activity in obese individuals. Medicine & Science in Sports & Exercise, 33, 1287-1291.
4.
Amara, C.E., & Wolfe, L.A. ( 1998). Reliability of noninvasive methods to measure cardiac autonomic function. Canadian Journal of Applied Physiology , 23, 396-408.
5.
American College of Obstetricians and Gynecologists. ( 2002). Hypertension in pregnancy. ACOG Technical Bulletin, (219, pp. 1-8). Washington, DC : Author.
6.
American College of Sports Medicine. (2006 ). ACSM’s guidelines for exercise testing and prescription (7th ed.). Baltimore, MD: Lippincott Williams & Wilkins.
7.
Avery, N.D., Wolfe, L.A., Amara, C.E., Davies, G.A., & McGrath, M.J. ( 2001). Effects of human pregnancy on cardiac autonomic function above and below the ventilatory threshold. Journal of Applied Physiology, 90, 321-328.
8.
Bianco, A.T., Smilen, S.W., Davis, Y., Lopez, S., Lapinski, R., & Lockwood, C.J. (1998). Pregnancy outcome and weight gain recommendations for the morbidly obese woman. Obstetrics & Gynecology, 91, 97-102.
9.
Blaber, A.P., Yamamoto, Y., & Hughson, R.L. ( 1995). Methodology of spontaneous baroreflex relationship assessed by surrogate data analysis. American Journal of Physiology , 268, H1682-H1687.
10.
Brown, C.A., Lee, C.T., Hains, S.M.J., & Kisilevsky, B.S. (2008). Maternal heart rate variability and fetal behavior in hypertensive vs. normotensive pregnancies. Biological Research for Nursing, 10, 134-144.
11.
Brown, C.A., Wolfe, L.A., Hains, S., Pym, J., & Parker, J.O. ( 1994). Early low intensity home exercise after coronary artery bypass graft surgery. Journal of Cardiopulmonary Rehabilitation , 14, 238-245.
12.
Brown, C.A., Wolfe, L.A., Hains, S., Ropchan, G., & Parlow, J. ( 2004). Heart rate variability following coronary artery bypass graft surgery as a function of recovery time, posture, and exercise. Canadian Journal of Physiology & Pharmacology, 82, 457-464.
13.
Canadian Guidelines for Body Weight Classification in Adults. (2003). Health Canada Publications Centre , Ottawa, Canada. Retrieved from www.healthcanada.gc.ca/nutrition
14.
Clapp, J.F. III. ( 1996). The effect of continuing regular endurance exercise on the physiologic adaptations to pregnancy and pregnancy outcome. American Journal of Sports Medicine, 24, S28-S29.
15.
Clapp, J.F., & Dickstein, S. ( 1984). Endurance exercise and pregnancy outcome. Medicine & Science in Sports & Exercise, 16, 556-562.
16.
Charlesworth, S.A., Wolfe, L.A., & Davies, G.A. ( 2006). Physicochemical analysis of acid-base responses to prolonged moderate exercise in late gestation. Applied Physiology, Nutrition, and Metabolism, 31, 744-752.
17.
Damm, P., Breitowicz, B., & Hegaard, H. ( 2007). Exercise, pregnancy, and insulin sensitivity: What is new?Applied Physiology, Nutrition, & Metabolism Physiologie Appliquee, Nutrition et Metabolisme, 32, 537-540.
18.
Davies, G.A., Wolfe, L.A., Mottola, M.F., & MacKinnon, C. ( 2003). Joint SOGC/Canadian Society for Exercise Physiology clinical practice guideline: Exercise in pregnancy and the postpartum period. Canadian Journal of Applied Physiology, 28, 330-341.
19.
Doherty, D.A., Magann, E.F., Francis, J., Morrison, J.C., & Newnham, J.P. ( 2006). Pre-pregnancy body mass index and pregnancy outcomes . International Journal of Gynaecology & Obstetrics, 95, 242-247.
20.
Dye, T.D., Knox, K.L., Artal, R., Aubry, R.H., & Wojtowycz, M.A. (1997). Physical activity, obesity and diabetes in pregnancy. American Journal of Epidemiology , 146, 961-965.
21.
Edwards, L.E., Hellerstedt, W.L., Alton, I.R., Story, M., & Himes, J.H. ( 1996). Pregnancy complications and birth outcomes in obese and normal-weight women: Effects of gestational weight change. Obstetrics & Gynecology, 87, 389-394.
22.
Ekholm, E.M., Piha, S.J., Antila, K.J., & Erkkola, R.U. ( 1993). Cardiovascular autonomic reflexes in mid-pregnancy. British Journal of Obstetrics & Gynecology, 100, 177-182.
23.
Eneroth-Grimfors, E., Westgren, M., Ericson, M., Ihrman-Sandahl, C., & Lindblad, L.E. (1994). Autonomic cardiovascular control in normal and preeclamptic pregnancy. Acta Obstetricia et Gynecologica Scandinavica, 73, 680-684.
24.
Felber Dietrich, D., Ackermann-Liebrich, U., Schindler, C., Barthélémy, J-C. , Brändli, O., Gold, D.R., ... Gaspoz, J.M. (2008). Effect of physical activity on heart rate variability in normal weight, overweight and obese subjects: Results from the SAPALDIA study. European Journal of Applied Physiology, 104, 557-565.
25.
Feldman, R.D., Campbell, N., Larochelle, P., Bolli, P., Burgess, E.D., Carruthers, G., . . . Zarnke, K.B. ( 1999). Canadian recommendations for the management of hypertension . Canadian Medical Association Journal, 161, S1-S22.
26.
Greenwood, J.P., Scott, E.M., Stoker, J.B., Walker, J.J., & Mary, D.A. ( 2001). Sympathetic neural mechanisms in normal and hypertensive pregnancy in humans. Circulation, 104, 2200-2204.
27.
Hainsworth, R. ( 1996). The physiological approach to cardiovascular reflexes . Clinical Science, 91, 43-49.
28.
Helmreich, R.J., Hundley, V., & Varvel, P. ( 2008). The effect of obesity on heart rate (heart period) and physiologic parameters during pregnancy. Biological Research for Nursing, 10, 63-78.
29.
Hua, L.P.T., Brown, C.A., Hains, S.J.M., Godwin, M., & Parlow, J. ( 2009). Effects of low intensity exercise conditioning on blood pressure, heart rate, and autonomic modulation of heart rate in men and women with mild hypertension. Biological Research for Nursing, 11, 129-143.
30.
Iellamo, F., Hughson, R.L., Castrucci, F., Legramante, J.M., Raimondi, G., Peruzzi, G., . . . Tallarida, G. ( 1994). Evaluation of spontaneous baroreflex modulation of sinus node during isometric exercise in healthy humans. American Journal of Physiology, 267, H994-H1001.
31.
Kumari, A.S. ( 2001). Pregnancy outcome in women with morbid obesity. International Journal of Gynecology & Obstetrics, 73, 101-107.
32.
Kuo, C.D., Chen, G.Y., Yang, M.J., Lo, H.M., & Tsai, Y.S. ( 2000). Biphasic changes in autonomic nervous activity during pregnancy. British Journal of Anesthesia, 84, 323-329.
33.
Laederach-Hofmann, K., Mussgay, L., & Ruddel, H. ( 2000). Autonomic cardiovascular regulation in obesity. Journal of Endocrinology, 164, 59-66.
34.
Lu, G.C., Rouse, D.J., DuBard, M., Cliver, S., Kimberlin, D., & Hauth, J.C. ( 2001). The effect of the increasing prevalence of maternal obesity on perinatal morbidity. American Journal of Obsetrics & Gynecology, 185, 845-849.
35.
Mattu, G.S., Heran, B.S., & Wright, J.M. ( 2004). Overall accuracy of the BpTRU: An automated electronic blood pressure device. Blood Pressure Monitoring. 9, (pp. 47-52).
36.
Miyake, Y., Ohnishi, M., Fujii, T.K., Yamamoto, T., Yoneda, C., Takahashi, S., ... Ichimaru, Y. ( 2002). The effects of postural changes of baroreflex gain in normal and hypertensive pregnancies. Clinical & Experimental Hypertension, 24, 23-31.
37.
Myslivecek, P.R., Brown, C.A., & Wolfe, L.A. ( 2002). Effects of physical conditioning on cardiac autonomic function in healthy middle-aged women. Canadian Journal of Applied Physiology, 27, 1-18.
38.
Pagani, M., Somers, V., Furlan, R., Dell’Orto, S., Conway, J., Baselli, G., . . . Malliani, A. ( 1988). Changes in autonomic regulation induced by physical training in mild hypertension. Hypertension, 12, 600-610.
39.
Paller, M.S. ( 1998). Hypertension in pregnancy. Journal of the American Society of Nephrology, 9, 314-321.
40.
Parati, G., Casadei, R., Groppelli, A., Di Rienzo, M., & Mancia, G. ( 1989). Control of finger and intra-arterial blood pressure monitoring at rest and during laboratory testing. Hypertension, 13, 647-655.
41.
Parlow, J., Viale, J.P., Annat, G., Hughson, R., & Quintin, L. ( 1995). Spontaneous cardiac baroreflex in humans. Control with drug-induced responses. Hypertension, 25, 1058-1068.
42.
Piccirillo, G., Vetta, F., Viola, E., Santagada, S., Ronzoni, S., & Caffiafesta, M. (1998). Heart rate and blood pressure variability in obese normotensive subjects. International Journal of Obesity, 25, 741-750.
43.
Pivarnik, J.M., Lee, W., Clark, S.L., Cotton, D.B., Spillman, H.T., & Miller, J.F. ( 1990). Cardiac output responses of primigravid women during exercise determined by the direct Fick technique. Obstetrics & Gynecology, 75, 954-959.
44.
Robertson, R.J., & Noble, B.J. ( 1997). Perception of physical exertion: Methods, mediators, and applications. Exercise & Sport Sciences Reviews, 25, 407-452.
45.
Rossi, M., Marti, G., Ricordi, L., Fornasari, G., Finardi, G., Fratino, P., ... Bernardi, L. ( 1989). Cardiac autonomic dysfunction in obese subjects. Clinical Science, 76, 567-572.
46.
Sebire, N.J., Jolly, M., Harris, J.P., Wadsworth, J., Joffe, M., Beard, R.W., ... Robinson, S. ( 2001). Maternal obesity and pregnancy outcome: A study of 287,213 pregnancies in London. International Journal of Obesity & Related Metabolic Disorders, 25, 1175-1182.
47.
Silver, H.M., Seebeck, M., & Carlson, R. ( 1998). Control of total blood volume in normal, preeclamptic, and nonproteinuric gestational hypertensive pregnancy by simultaneous measurement of red blood cell and plasma volumes. American Journal of Obstetrics and Gynecology, 179, 87-93.
48.
Smit, A.A.J., Wieling, W., & Karemaker, J.M. (1996). Clinical approach to cardiovascular reflex testing. Clinical Science, 91, 108-112.
49.
Sorensen, T.K., Williams, M.A., Lee, I.M., Dashow, E.E., Thompson, M.L., & Luthy, D.A. ( 2003). Recreational physical activity during pregnancy and risk of preeclampsia. Hypertension, 41, 1273-1280.
50.
Stephansson, O., Dickman, P.W., Johansson, A., & Cnattingius, S. (2001). Maternal weight, pregnancy weight gain, and the risk of antepartum stillbirth. American Journal of Obstetrics & Gynecology, 184, 463-469.
51.
Swansburg, M., Brown, C.A., Hains, S.J.M., Smith, G.N., & Kisilevsky, B.S. (2005). Maternal cardiac autonomic function and fetal heart rate in preeclamptic compared to normotensive pregnancies: An exploratory study. Canadian Journal of Cardiovascular Nursing , 15, 42-52.
52.
Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. (1996). Heart rate variability. Standards of measurement, physiological interpretation, and clinical use. European Heart Journal, 17, 354-381.
53.
Tuck, M.L. ( 1992). Obesity, the sympathetic nervous system, and essential hypertension. Hypertension, 19, 167-177.
54.
Voss, A., Malberg, H., Schumann, A., Wessel, N., Walther, T., & Stepan, H. ( 2000). Baroreflex sensitivity, heart rate, and blood pressure variability in normal pregnancy. American Journal of Hypertension , 13, 1218-1225.
55.
Walsh, S.W. ( 2007). Obesity: A risk factor for preeclampsia. Trends in Endocrinology & Metabolism, 18, 365-370.
56.
Weissgerber, T.L., Wolfe, L.A., & Davies, G.A. ( 2004). The role of regular physical activity in preeclampsia prevention. Medicine & Science in Sports & Exercise , 36, 2024-2031.
57.
Weissgerber, T.L., Wolfe, L.A., Davies, G.A.L., & Mottola, M.F. ( 2006). Exercise in the prevention and treatment of maternal-fetal disease: A review of the literature. Applied Physiology, Nutrition, and Metabolism, 31, 661-674.
58.
Wolfe, L.A. ( 2005). Pregnancy. In James S. Skinner (Ed.), Exercise testing and exercise prescription for special cases (3rd ed., pp. 377-389). Philadelphia, PA: Lippincott Williams & Wilkins .
59.
Wolfe, L.A., Preston, R.J., Burggraf, G.W., & McGrath, M.J. ( 1999). Effects of pregnancy and chronic exercise on maternal cardiac structure and function. Canadian Journal of Physiology and Pharmacology, 77, 909-917.
60.
Wolfe, L.A., & Weissgerber, T.L. (2003). Clinical physiology of exercise in pregnancy: A literature review. Journal of Obstetrics and Gynaecology of Canada, 25, 473-483.
61.
Yamamoto, Y., & Hughson, R.L. ( 1991). Coarse-graining spectral analysis: New method for studying heart rate variability. Journal of Applied Physiology, 71, 1143-1150.
