**7. Application of a pedometer as a health care improving tool**

## **7.1 Non-pregnant condition**

*Sugar Intake - Risks and Benefits and the Global Diabetes Epidemic*

developing gestational diabetes mellitus (GDM) [19].

**6. Application of a pedometer as an exercise-monitoring tool**

A rationale for the application of a pedometer for exercise quantification has been tested in non-pregnant women using doubly-labelled water, a gold standard measurement of free-living energy expenditure with that of the accelerometer. The study demonstrated that the accelerometer is an alternative objective tool for the evaluation of exercise quantitatively in non-pregnant individuals [20]. Furthermore, Harrison et al. compared the accelerometer and pedometer as well as the subjective exercise assessment questionnaire, the International Physical Activity Questionnaire (IPAQ ), showing that the pedometer was superior to the accelerometer and IPAQ in an objective assessment of exercise during

muscles, making them the major user of carbohydrates in the body [9]. There are two pathways for the use of carbohydrates in the skeletal muscles. One is a pathway by which the GLUT4 that is present in muscle cells is transported to the surface of cell membranes (translocation) and glucose uptake then occurs when insulin binds with receptors on the surface of the muscle cell membranes [9]. The other pathway is one by which insulin-independent glucose uptake is made possible by translocation of GLUT4 by adenosine monophosphate-dependent protein kinase that is activated in conjunction with muscle contractions [9]. Although the GLUT4 on the cell surface disappears 2 to 3 hours after exercise, the turn-over of the translocation of GLUT4 is upregulated by the exercise in response to the same levels of blood insulin concentrations [9]. Furthermore, the gene transcription of GLUT4 is enhanced after 10 or more hours after exercise [9]. As a result, even though glucose from the blood is uptaken by skeletal muscles, blood glucose levels are almost unaltered. However, although patients with type 2 DM are able to increase the uptake of glucose into skeletal muscle through exercise, they experience a decrease in the blood glucose level through the suppression of gluconeogenesis in the liver due to hyperinsulinemia [9]. Further, post-exercise promotion of glycogen synthesis and insulin sensitivity causes a drop in blood glucose levels. Recently, participation of angiotensin-(1–7), a vasoactive peptide of the renin-angiotensin system is demonstrated in enhanced skeletal muscle insulin sensitivity after a bout of exercise [16]. It is known that patients treated with insulin and hypoglycaemic agents are particularly susceptible to hypoglycaemia from the day of exercise to the following day [8]. Similar to type 2 DM, carbohydrate metabolism switches into insulin resistance in the latter half of pregnancy. Therefore, one may speculate that the blood glucose levels might be influenced by exercise during pregnancy. However, Artal et al. measured the blood glucose levels, insulin concentrations, and glucagon concentrations in women in the third trimester of normal pregnancies before and after a 15-minute treadmill exercise. The results indicated that the post-exercise blood glucose level and insulin level did not change, but that the glucagon level was elevated [17]. In contrast, Soultanakis et al. showed that continuous prolonged exercise in pregnancy with about 55% VO2 or higher could result in hypoglycaemia after 45–60 minutes of continuous exercise, suggesting the importance of appropriate exercise plans in the management of blood glucose levels in women with impaired glucose tolerance [18]. In line, Artal suggested that one moderate bout of exercise of 30–45 minutes/day and one bout of exercise after each meal to burn at least 200 kcal or more per day is effective in obtaining or maintaining euglycemia during pregnancy [17]. It is noteworthy that a regular programme of exercise before pregnancy appears to lower the risk of

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pregnancy [21].

The application of a pedometer for health improvement has been examined in the non-pregnancy context. Richardson et al. reported a meta-analysis of pedometer-based walking interventions and weight loss [22]. They searched 6 electronic databases and found nine studies which met their inclusion criteria. Those studies demonstrated that pedometer-based walking programs resulted in a modest amount of weight loss, on average 0.05 kg per week during the interventions. Mitsui et al. showed gender differences in the relationship between steps/day and BMI in Japanese adults [23]. Walker et al. showed that a 10,000 steps per day for 6 months resulted in a 3.0 cm loss in waist circumference, whereas there were no differences in body mass index among 142 subjects, including both genders [24]. The application of pedometer was examined for ovulation induction along with administration of clomiphene citrate in overweight women with polycystic ovary syndrome with greater number of spontaneous ovulation and pregnancy [25]. With respect to the effect of exercise monitored with a pedometer on carbohydrate metabolism, Huus et al. showed that physical activity assessed with a pedometer in healthy schoolchildren at the age of 8 and 12 longitudinally improved insulin sensitivity and decreased fasting C-peptide irrespective of the BMI [26]. This report is interesting because they investigated the association of exercise monitored with pedometer and insulin sensitivity qualitatively.

### **7.2 Pregnant condition**

The clinical use of pedometers in obese pregnant women has been a controversial topic. Streuling et al. performed a meta-analysis on clinical trials which dealt with the application of a pedometer in the management of gestational weight gain [27]. Out of 1380 studies, they identified 12 trials that met their inclusion criteria. In seven trials, gestational weight gain was lower in the exercise group than in the control group, whereas five trials showed a lower GWG in the control groups. In Asia, Jiang et al. reported that pregnant women being physically active assessed by pedometer had less weight gain during pregnancy [28]. In this report, the activity levels were divided into 4 groups as sedentary (< 5000 daily steps), low active (5000–7000 daily steps), somewhat active (7500–10,000 daily steps) and active (≥10,000 daily steps). In accordance with Jiang's report, Cohen and Koski reported that both more than 5000 steps/day assessed by pedometer and daily energy intakes within 300 kcal of estimated energy requirements minimised postpartum weight retention of healthy pregnant women [29]. Although the application of a pedometer for the control of gestational weight gain seems controversial based on the abovementioned meta-analysis, one of the most important questions is related to the use of a pedometer by obese women, because they may be reluctant to exercise and that could be one of the reasons why they are obese. Even in a recent multiinstitutional study conducted in Australia which used a randomised controlled trial in order to assess a pedometer-based intervention to increase activity and reduce excessive weight gain in pregnant women, the conclusion of the study showed negative results with the notion that the improvement of compliance with activity data recording and behavioural interventions delivered [30]. However, there are promising reports on the use of a pedometer for the management of overweight and obese pregnant women by active intervention with individualised nutritional support and individual exercise plans. For example, one study described an intervention at

16 to 20 weeks of gestation in overweight and obese women. The average number of steps after the intervention was over 10,000, along with the intake of 2000 kcal/day. This approach resulted in the prevention of excessive weight gain as well as excessive postpartum weight retention [31]. The study clearly demonstrated that both nutritional and exercise interventions are necessary in order to achieve reasonable outcomes in the management of glucose metabolism in obese pregnant women. In comparison of a smartphone pedometer with a reference pedometer, The Yamax Digiwalker, Tokyo, Japan, a smartphone pedometer is even superior at a low walking speed, suggesting a smartphone pedometer might be superior to pregnant women who are not expected to walk faster. [32]. So, there is no problem in using a smartphone pedometer instead of stand-alone pedometer.
