Efectos Del Ejercicio Físico De Alta Intensidad Y Sobrecarga En Parámetros De Salud Metabólica En Mujeres Sedentarias.docx

Efectos del ejercicio físico de alta intensidad y sobrecarga en parámetros de salud metabólica en mujeres sedentarias, prediabéticas con sobrepeso u obesidad Effect of sprint interval training and resistance exercise on metabolic markers in overweight women

Cristian Álvarez1,a, Rodrigo Ramírez2,b, Marcelo Flores3,4,c, Cecil Zúñiga5,d, Carlos A. Celis-Morales6,e Centro de Salud Familiar de Los Lagos. Centro de Promoción de Salud de la mujer, Región de Los Ríos, Chile. 2 Departamento de Ciencias de la Actividad Física, Universidad de Los Lagos, Osorno, Chile. 3 Unidad de Kinesiología, Hospital de Carabineros de Chile, Santiago, Chile. 4 Departamento de Fisiología, Universidad de Melbourne, Australia. 5 Departamento de Educación Física, Universidad San Sebastián, Región de Los Ríos, Chile. 6 Centro de Investigación en Nutrición Humana, Instituto de Investigación en Envejecimiento y Salud. Universidad de Newcastle. Inglaterra. Reino Unido. a Profesor de Educación Física, MSc. Entrenamiento Deportivo. b Profesor de Educación Física, MSc. Fisiología del Ejercicio. c Kinesiólogo, MSc. Fisiología del Ejercicio. d Kinesiólogo, MSc. Educación, ISAK nivel III. e Doctor en Ciencias Cardiovasculares y Biomédicas (PhD). 1

Correspondencia a:

Background: Physical activity is associated with an improvement in cardiovascular health, however there is a paucity of information about the effects of sprint interval training on individuals with high metabolic risk. Aim: To determine the effects of three exercise programs on anthropometric and metabolic markers in overweight, sedentary and prediabetic women. Material and Methods: Forty three women were ascribed to four groups matched by body mass index and body fat: high intensity intervals (HIT, n = 12), resistance (R, n = 8), combined group (HIT +R, n = 10) and control group (CG, n = 13). Participants completed 12 weeks of exercise intervention. Body mass index, waist circumference, percentage of fat mass measured by impedanciometry, blood pressure, fasting glucose, insulin and homeostasis model assessment for insulin resistance (HOMAlR) and fitness assessed using the two km walk test were measured at baseline and after the training period. Results: No changes in anthropometric and body composition variables were observed. However, in HIT and R groups, significant reductions were observed on fasting glucose (5.4 and 16.6% respectively), insulin (18.6 and 43.4% respectively) and HOMAIR (24.1 and 55.4% respectively), 72 hours after the intervention. No significant changes were found for the observed values in the combined and control groups. Conclusions: HIT and resistance training improve glycemic control and insulin sensitivity in females with a high metabolic risk. (Rev Med Chile 2012; 140:1289-1296). Key words: Exercise; Insulin Resistance; Obesity; Sedentary Lifestyle.

Overweight and obesity are states that are associated with the development of insulin resistance (IR), type 2 diabetes (T2D) and cardiovascular disease (CVD) 1-3. Additionally, sedentary lifestyle has been pointed out as another relevant factor in the increase of these pathologies3-5. In Chile, 93% of women are sedentary and 64% are overweight or obese and CVDs are currently the main cause of death in the country6,7. Despite the association between the practice of physical activity (PA) and the reduction of CVD8, AF levels remain low in the population9. This has led to the proposal of new AF recommendations for the adult population, which reduce the traditional 150 min of AF per week to 20 min of AF of greater intensity and with shorter duration (eg 3 times per week) 10,11. This change could be an important step to increase the levels of FA, since the lack of time has been identified as one of the main barriers to the practice of PA in the adult population12. However, in relation to the effects of this new practice of AF in people with metabolic risk is limited. Taking into account the levels of sedentary lifestyle, obesity, DT2 and CVD in Chile, it is necessary to design, and evaluate other models of FA, that are feasible to be implemented in local health services and programs throughout the country. Therefore, the objective of this study was to evaluate the impact of 3 AF programs on anthropometric parameters and cardiovascular health in sedentary, pre-diabetic and overweight women.

Material and methods Participants

Forty-three women participated in the study (n = 43), who were recruited at the Family Health Center of Los Lagos (CESFAM), Los Ríos Region, Chile. The study design corresponds to an experimental study with simple random sampling. The participants were divided into four groups: interval program (PI), overload program (PS), mixed program (PI + PS) and control group (GC). The allocation of the participants in each group was matched according to BMI and% fat mass. The sample size was estimated using observed changes in plasma insulin (delta = 2.16 mU / L, SD = 1.38) in a group operated with different exercise programs13. A total of 9 participants per group gives a power of 80% and an α of 0.05. The inclusion criteria were: a) sedentary (exercise <30 min / week), b) BMI> 25.0 kg / m2, c) blood glucose level 100 to <125 mg / dl14. Exclusion criteria were: a) history of osteoarticular disease, ischemic, arrhythmias, tachycardia and / or chronic obstructive pulmonary disease; b) with pharmacological treatment for metabolic alterations. This study was carried out considering the Declaration of Helsinki and was approved by the ethics committees of CESFAM Los Lagos, Osorno, Chile. All participants gave their written informed consent prior to the intervention.

Procedures Body weight, fat mass (MG) and muscle mass (MM) were determined, using a digital scale of bioimpedance of feet and hands (OMRON®, Model HBF-INT). The height was measured with a 0.1 cm precision height rod (Health or Meter®, USA). BMI was calculated by dividing body weight by height squared (kg / m2)

and overweight was defined as BMI> 25 kg / m2. The waist circumference was measured just above the line of the iliac crest15 with an inextensible tape and precision of 0.1 cm (Hoechstmass®, West Germany 1-150 cm). Blood pressure was determined with a digital monitor (OMRON, model HEM742INT). Each participant remained in a seated position at least 15 minutes prior to the measurement, reporting only the average of three measurements. Fasting blood samples (4 ml) were obtained between 8:00 AM and 11:00 AM (Preintervention, 24 h and 72 h Postintervention). Glicemia was determined with an enzymatic method (Trinder, Genzyme Diagnostics, Canada) and insulin was determined by RIA (DPC, Los Angeles, CA). Insulin resistance was determined with HOMAIR16. The UKK test was applied to determine bipedal translation capacity17. Sociodemographic and health questionnaires were applied to determine age, history of pharmacological treatment, family history of diseases indicated in the inclusion and exclusion criteria.

Design of intervention programs Programs of interval physical exercise (PI): consisted of performing careers and recovery pauses in an interval way until completing a volume of 20 min of AF per day and twice a week. In each session the participants completed 7 high-intensity racing intervals (> 85% of the maximum heart rate (220-Age), each interval lasted 20 s and increased by 2 s (10%) every 2 weeks, while that the recovery interval of 120 s, decreased by 5 s (~ 4%) every 2 weeks (Table 1).

Table 1. Description of the physical exercise protocols used in the intervention

Program of physical exercise of overload (PS): consisted of performing 5 different exercises of overload (squat, flexoextension of biceps, flexo-extensions of ankle, flexo-extension of shoulders and flexo-extensions of elbow). Each exercise was performed for 1 minute (reaching muscle failure) and repeated 3 times per session, with pauses of 2 min of recovery between each series18 (Table 1). Program of Combined Physical Exercise (PI + PS): consisted of performing both exercise programs on non-consecutive days, making a total of 5 days of physical exercise per week (Table 1).

Diet, Physical Activity and Adherence All participants were instructed not to change their diet and FA patterns during the course of the intervention. The adherence presented by the three groups was PI (85%), PS (95%) and PI + PS (74%).

Statistics The data are presented as mean ± standard deviation. The Shapiro-Wilk test was applied to determine if the variables corresponded to a normal distribution. Differences between Pre and Post

intervention were determined with Student t test for related samples. To determine if there were significant differences in quantitative variables between the four Pre-intervention groups, two-way ANOVA analysis was applied and to determine differences between pretest, post-test 24 h and post-test 72 h, oneway ANOVA was applied, the test Bonferoni was used to detect where these differences were. The analyzes were adjusted for age and adherence to the intervention program. All analyzes were performed in SPSS (version 19). The level of significance accepted was p <0.05.

presented differences between the groups prior to the intervention (p <0.001), being significantly higher in the PI group compared to the PI + PS group and the control group. However, diastolic blood pressure, cardio-respiratory test UKK, glycemia, insulinemia and HOMAIR did not show significant differences between groups prior to the intervention (Table 2). Table 3. Metabolic characteristics of the participants Pre and Post intervention stratified by group.

Results Table 2 describes the anthropometric variables stratified by AF Pre and Post intervention program. The age and anthropometric characteristics (weight, height, BMI, waist circumference and% fat mass) of the participants did not show significant differences between groups prior to the intervention. Table 2. Anthropometric and physical condition characteristics of the participants Pre and Post intervention stratified by group

In relation to the metabolic variables (Table 3), systolic blood pressure

After 12 weeks of intervention, the anthropometric variables did not show significant changes between the intervention groups. In the UKK cardiorespiratory test, the PI and PI + PS groups significantly reduced the time used to travel 2 km after the 12 weeks of intervention (p <0.001), but not the PS and GC groups. Systolic blood pressure showed a significant reduction Post intervention only in the PI group (p = 0.043). The metabolic markers of glycemia, insulinemia and HOMAIR were measured 24 h and 72 h post intervention. The glycemia shows a significant reduction of 6.7% in the PI group (p = 0.011) and 7.4% in the PS group (p =

0.019), but not in the group PI + PS and GC at 24 h Post intervention . No significant reductions were found in insulin and HOMAIR at 24 h Post intervention in any of the groups. However, these variables showed a significant reduction at 72 h Post intervention in the PI and PS groups, but not in the PI + PS and GC group. The magnitude of these reductions were 5.4% and 6.5% in glycemia levels, 18.6% and 43.4% in insulinemia, 24.1% and 55.4% in HOMAIR in the PI group and PS, respectively. The average% of reductions (delta 24 and 72 h Post intervention) are presented in Figure.1.

Groups are marked as (PI: Interval Program, PS: Overload Program, PI + PS: Combined Group and GC: Control Group). Significant differences between pre, 24 h post and 72 h post were determined with one-way ANOVA. The models were adjusted for age and program attendance. Values of significance are indicated as * p <0.05, ** p <0.01.

Discussion

Figure 1. Changes in glycemia and HOMAir after 12 weeks of intervention. Data presented as mean ± standard error of the mean. Graphs a and c show the levels of glycemia and insulin resistance preintervention, 24 h and 72 h post intervention. Graphs b and d show the% reduction (Post72h-Pre) in glycemia and HOMAIR post intervention.

The results of this study indicate that the application of more intense PA programs, such as the PI and PS programs, are effective tools for the reduction of IR levels in sedentary, pre-diabetic and overweight women. It is also important to note that the design of shorter AF programs can be used as a strategy to increase the practice and adherence to AF programs in adults with metabolic risk, which is a necessity considering the national reality in relation to the high levels of sedentary lifestyle (~ 93%), overweight or obesity (~ 64%) and prevalence of diabetes (~ 9%) in women6, 7. The interventions proposed in this investigation did not produce changes in BMI, waist circumference and% fat mass in any of the 3 groups operated on. Our results agree with previous studies where similar AF programs in obese women did not produce significant changes in

adiposity19,20. These results could be explained by the short intervention period. Although no changes were detected in adiposity markers in our study, the proposed FA programs significantly reduced post-intervention glycemia levels. Glycemic control is an important factor in the treatment of T2D and is associated with vascular complications in diabetic patients21. This study reported an average reduction of 6.1% and 6.9% in post-intervention blood glucose levels in the PI and PS group, respectively. These changes were lower than those reported by Little and cols19, who reported a reduction of 13% after 6 sessions of (PI) during 2 weeks of intervention. Similar reductions in glycemia (15.6%) were reported by Cauza et al22, after an intervention with PS exercises. This difference in blood glucose reduction could be explained by the type of patients who underwent surgery, since both studies involved diabetic patients and, as previously mentioned, the benefits of AF are greater in people with metabolic risk (overweight, sedentary and diabetic). 23.24. The average reductions in insulinemia (PI ~ 16%, PS ~ 27.6) and HOMAIR (PI ~ 17%; PS ~ 38), reflect the vascular benefits associated with the application of PI and PS exercises in women with metabolic risk. These reductions have important clinical implications due to the association between IR and the increase in mortality levels attributed to CVD25. The reduction in insulinemia and HOMAreported in our study are similar to the benefits obtained with traditional training programs, where 150-300 min per week of aerobic exercise (65% of VO2MAX) reduces in 22% the levels of insulinemia and improvement in 32%

insulin sensitivity, after 7 weeks of training in overweight women and family history of diabetes26. However, it is important to note that the greater reduction in HOMAIR associated with the PS group compared to the PI group could be explained by differences in the volume and training time in our study (Table 1). Similarly, the lack of adherence to the program could be one of the factors that could explain the non-significant changes in the PI + PS group. However, it is important to note that all three programs have a clear tendency to reduce glycemia and insulin resistance. The potential mechanisms through which PI or PS programs improve glycemic control and insulin sensitivity are interesting considering that there were no changes in the variables of body composition. It has recently been reported that programs of 4 repetitions interval of 30 s, produce a minimum energy expenditure of ~ 40-80 kcal but nevertheless, reduce muscle glycogen between 30% and 45% through the metabolic pathway of AMPK that plays a role paramount in the translocation of GLUT4 and muscle glucose consumption27. Interestingly, the level of reduction in muscle glycogen induced by 4 repetitions of 30 s of PI exercises is similar to that induced by a 90-min session of moderate intensity aerobic exercise28. Additionally, another mechanism that could explain the reduction in IR is muscle adaptation to training programs. It has been reported that diabetic patients or those with metabolic risk have a reduced capacity for mitochondrial oxidation, 29 and that interventions similar to those proposed in our study increase mitochondrial oxidation capacity in both healthy subjects30 and metabolic risk31.

Additionally, changes in systolic blood pressure (SBP) were detected in the interval group, this could be explained because the PI group had higher levels of SBP than the other Pre-intervention groups. The mechanisms by which PI exercises reduce SBP have not been fully elucidated, but they may be mediated by a reduction in sympathetic nervous system vascular control32 and vasodilation mechanisms associated with an increase in nitric oxide production by the body. endothelium33. It is important to highlight some strengths of the present study, as it was matched according to BMI and fat mass levels of the groups operated on. Additionally, the design of the exercise programs was carried out considering protocols of simple application, and feasible to be replicated in other CESFAM at a national level. Finally, standardized techniques for the measurement of anthropometric and metabolic parameters were considered. However, it is important to mention potential limitations in the design of the study that should be considered in future research. Within the limitations is the control of caloric intake during the intervention, since the changes detected in metabolic markers could be affected by changes in eating patterns, however, the participants were constantly instructed not to modify their diet. Similarly, physical activity levels were not objectively controlled during the intervention, however, the nonperformance of physical activity outside the intervention programs was emphasized. Another limitation was the age distribution in the groups, the average age was higher in the PS group which could explain why said program shows greater reductions, however, the age was adjusted in the statistical models and no differences were detected in the

magnitude and direction of the results. Finally, adherence to the intervention programs is another factor of confusion, therefore the analyzes were adjusted by level of assistance. In conclusion, the PI and PS programs are effective alternatives for the reduction of insulin resistance in sedentary, prediabetic and overweight women. The total exercise time required per week to produce metabolic benefits was 60 min in the PI group and 90 min in the PS group, representing 40% and 60%, respectively, of the traditional AF recommendations (150 min x week) 10. Considering that the lack of time has been one of the main justifications for the non-practice of physical activity, we believe that this strategy of reducing exercise time could be a viable alternative to increase adherence to intervention programs. The exercise programs presented in this research show that implementing shorter programs in Family Health Centers at the national level is an alternative prescription tool, easy to implement and effective in reducing cardiovascular risk associated with insulin resistance in patients with metabolic risk.

Acknowledgments: To all the participants, for their commitment to the program. Carmen Gloria Flores, Director of CESFAM Los Lagos and Leslie Ruiz, Coordinator of the Health Promotion Program, of CESFAM, for their administrative management of the

project.

References 1. McLaughlin T, Allison G, Abbasi F, Lamendola C, Reaven G. Prevalence of insulin resistance and associated cardiovascular disease risk factors among normal weight, overweight, and

obese individuals. Metabolism. 2004; 53 (4): 495-9. 2. Reaven GM. Insulin resistance: the link between obesity and cardiovascular disease. Med Clin North Am. 2011; 95 (5): 875-92. 3. Celis-Morales CA, Pérez-Bravo F, Ibanes L, Sanzana R, Hormazabal E, Ulloa N, et al. Insulin resistance in Chileans of European and indigenous descent: evidence for an ethnicity x environment interaction. PloS One. 2011; 6 (9): e24690. 4. Proper KI, Singh AS, van Mechelen W, Chinapaw MJM. Sedentary behaviors and health outcomes among adults: a systematic review of prospective studies. Am J Prev Med. 2011; 40 (2): 174-82. 5. Thorp AA, Owen N, Neuhaus M, Dunstan DW. Sedentary behaviors and subsequent health outcomes in adults a systematic review of longitudinal studies, 1996-2011. Am J Prev Med. 2011; 41 (2): 207-15. 6. Villalón GC GG, Vera SS. Evolución de la mortalidad en Chile según causas de muerte y edad: 1990-2007. Publicacion Especial. Chile: Instituto Nacional de Estadistica; 2010. 7. MINSAL. Encuesta Nacional de Salud 2009-2010. Chile: Ministerio de Salud; 2010. 8. Ahmed HM, Blaha MJ, Nasir K, Rivera JJ, Blumenthal RS. Effects of physical activity on cardiovascular disease. Am J Cardiol. 2012; 109 (2): 288-95. 9. Dumith SC, Hallal PC, Reis RS, Kohl HW, 3rd. Worldwide prevalence of physical inactivity and its association with human development index in 76 countries. Prev Med 2011; 53 (1-2): 24-8.

10. Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011; 43 (7): 133459. 11. O'Donovan G, Blazevich AJ, Boreham C, Cooper AR, Crank H, Ekelund U, et al. The ABC of Physical Activity for Health: a consensus statement from the British Association of Sport and Exercise Sciences. J Sports Sci 2010; 28 (6): 573-91 12. Reichert FF, Barros AJD, Domingues MR, Hallal PC. The role of perceived personal barriers to engagement in leisure-time physical activity. Am J Public Health 2007; 97 (3): 515-9 13. Whyte LJ, Gill JMR, Cathcart AJ. Effect of 2 weeks of sprint interval training on health-related outcomes in sedentary overweight/obese men. Metabolism 2010; 59 (10): 1421-8 14. ADA. Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes care 1997; 20 (7): 118397. [ Links ] 15. Marfell-Jones M, Olds, T., Stewart, A., Carter, L. International standards for anthropometric assessment: ISAK 1st ed. Potchefstroom, South Africa: The International Society for the Advancement of Kinanthropometry (ISAK); 2006. 16. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin

concentrations in man. Diabetologia 1985; 28 (7): 412-9 17. Laukkanen RM, Kukkonen-Harjula TK, Oja P, Pasanen ME, Vuori IM. Prediction of change in maximal aerobic power by the 2-km walk test after walking training in middle-aged adults. Int J Sports Med 2000; 21 (2): 113-6

24. Armstrong MJ, Boule NG, Sigal RJ. Exercise interventions and glycemic control in patients with diabetes. JAMA 2011; 306 (6): 607

18. Saavedra C. Guía de actividad física para el adulto mayor. Santiago, Chile: Instituto Nacional del Deporte; 2006

25. Hu G, Qiao Q, Tuomilehto J, Eliasson M, Feskens EJM, Pyorala K, et al. Plasma insulin and cardiovascular mortality in non-diabetic European men and women: a meta-analysis of data from eleven prospective studies. Diabetologia 2004; 47 (7): 124556.

19. Little JP, Gillen JB, Percival ME, Safdar A, Tarnopolsky MA, Punthakee Z, et al. Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes. J Appl Physiol 2011; 111 (6): 1554-60

26. Barwell ND, Malkova D, Moran CN, Cleland SJ, Packard CJ, Zammit VA, et al. Exercise training has greater effects on insulin sensitivity in daughters of patients with type 2 diabetes than in women with no family history of diabetes. Diabetologia 2008; 51 (10): 1912-9.

20. Gibala MJ, Little JP, van Essen M, Wilkin GP, Burgomaster KA, Safdar A, et al. Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. J Physiol 2006; 575 (Pt 3): 901-11.

27. Towler MC, Hardie DG. AMPactivated protein kinase in metabolic control and insulin signaling. Circ Res 2007; 100 (3): 328-41

21. Ceriello A. The possible role of postprandial hyperglycaemia in the pathogenesis of diabetic complications. Diabetologia 2003; 46 Suppl 1: M9-16 22. Cauza E, Hanusch-Enserer U, Strasser B, Kostner K, Dunky A, Haber P. Strength and endurance training lead to different post exercise glucose profiles in diabetic participants using a continuous subcutaneous glucose monitoring system. Eur J Clin Invest 2005; 35 (12): 745-51 23. Gill JMR, Malkova D. Physical activity, fitness and cardiovascular disease risk in adults: interactions with insulin resistance and obesity. Clin Sci 2006; 110 (4): 409-25

28. Krssak M, Petersen KF, Bergeron R, Price T, Laurent D, Rothman DL, et al. Intramuscular glycogen and intramyocellular lipid utilization during prolonged exercise and recovery in man: a 13C and 1H nuclear magnetic resonance spectroscopy study. J Clin Endocrinol Metab 2000; 85 (2): 748-54 29. Ritov VB, Menshikova EV, Azuma K, Wood R, Toledo FGS, Goodpaster BH, et al. Deficiency of electron transport chain in human skeletal muscle mitochondria in type 2 diabetes mellitus and obesity. Am J Physiol Endocrinol Metab 2010; 298 (1): E49-58 30. Burgomaster KA, Howarth KR, Phillips SM, Rakobowchuk M, Macdonald MJ, McGee SL, et al. Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. J Physiol. 2008; 586 (1): 151-60.

31. Hood MS, Little JP, Tarnopolsky MA, Myslik F, Gibala MJ. Low-volume interval training improves muscle oxidative capacity in sedentary adults. Med Sci Sports Exerc 2011; 43 (10): 1849-56 32. Halliwill JR, Taylor JA, Eckberg DL. Impaired sympathetic vascular regulation in humans after acute dynamic exercise. J Physiol 1996; 495 (Pt 1): 279-88 33. Halliwill JR. Mechanisms and clinical implications of post-exercise hypotension in humans. Exerc Sport Sci Rev 2001; 29 (2): 65-70