Prescribing physical activity to prevent and manage gestational diabetes

Table 1 Contraindications to physical activity during pregnancy and warning signs for termination

Contraindications to exercise[19]	Significant cardiopulmonary disease, restrictive lung disease, incompetent cervix/cerclage, multiple gestation at risk for premature labor, persistent second- or third-trimester bleeding, placenta previa after 26 wk of gestation, premature labor during the current pregnancy, ruptured membranes, and preeclampsia/pregnancy-induced hypertension
Warning signs to terminate or avoid exercise	Vaginal bleeding, dyspnea prior to exertion, dizziness, headache, chest pain, muscle weakness, calf pain or swelling, preterm labor, decreased fetal movement, or amniotic fluid leakage

Table 2 Example using heart rate reserve to determine target hazard ratio range

Target HR range (40%-89% HRR)

Example patient: 30-year-old female

Resting HR: 78 beats per minute (bpm)

Maximum HR: 190 bpm (estimated as 220 minus age)

Formula for sample calculation:

Target HR = [(Max HR-Resting HR) × Desired Intensity)] + Resting HR

Lower end of HR range (40%) = [(190-78) × 0.40] + 78

(Low end of moderate intensity) = [112 × 0.40] + 78 = 45 + 78 = 123 bpm

Higher end of HR range (89%) = [(190-78) × 0.85] + 78

(High end of vigorous intensity) = [112 × 0.89] + 78 = 100 + 78 = 178 bpm

Target HR range (40%-89% HRR) = 123 to 178 bpm

HRR: Heart rate reserve.

Table 3 Recommended exercise prescription for women with gestational diabetes

Mode	Aerobic: Walk, stationary cycle, swim, aquatic activities, conditioning machines, prenatal exercise classes, prenatal yoga, seated exercises, and possibly jogging or running (if highly active before pregnancy)
	Resistance: Light or moderate resistance exercises
	Exercises to Avoid: Activities lying flat on the back and any that increase the risk of falling or abdominal trauma (e.g., contact or collision sports, horseback riding, downhill skiing, water skiing, soccer, outdoor cycling, basketball, most racquet sports, and scuba diving)
Intensity	If inactive: moderate-intensity aerobic activity (40%-59% HRR, or “somewhat hard”) during pregnancy and postpartum
	If already active or doing vigorous activity: moderate- to vigorous-intensity activity (40%-89% HRR, or “somewhat hard” to “hard”)
Frequency	3-7 d, spread throughout the week
	Better done on most, if not all, days of the week
Duration	30 min/session (range of 20-45 min)
	At least 150 min of moderate-intensity physical activity spread throughout the week
Progression	If just starting, increase duration of moderate exercise slowly; if already more active, maintain or lower intensity during pregnancy rather than attempting to progress to higher levels

HRR: Heart rate reserve. Reprinted by permission from (Colberg SR. Exercise and Diabetes: A Clinician’s Guide to Prescribing Physical Activity, American Diabetes Association, Alexandria, VA, United States, 2013. p. 110.).