A Non-Randomized Combined Program of Walking and Low-Load Resistance Exercise Improves Cognitive Function and Cardiometabolic Risk Factors in Community-Dwelling Elderly Women
Round 1
Reviewer 1 Report
After reviewing the article, I consider that it provides sufficient scientific contributions to validate the objective stated in the article, clearly showing how exercise intervention improves cognitive function in older women living in the community. However, I consider that the article needs more extensive and detailed conclusions and discussion in order to be published.
Author Response
Our Responses to Reviewer 1
We deeply appreciate the reviewers for their thoughtful comments. We did our best to address all the comments/critics point-by-point, which are highlighted in yellow color. Ten references are newly cited and listed on the last page.
Q1) I consider that the article needs more extensive and detailed conclusions and discussion in order to be published.
ANS1) Thanks. In response to the comments, the discussion is revised (please refer to lines 197-277, lines 238-243, and lines 240-245 in Discussion).
And the conclusions are revised as follows; “In this study, we found that a long-term exercise program consisting of walking and low-load and high-repetition resistance exercise is safe and feasible for community-dwelling older adults. As result, we found that the exercise intervention improved cognitive function, cardiometabolic risk factors, serum cytokines, and depressive symptoms in this study population. Furthermore, we showed that an improvement in cognitive function was significantly associated with improvements in depressive symptoms, insulin resistance, and muscular strength following an exercise intervention. These findings suggest that a structured exercise program can be recommended as a nonpharmacologic strategy for elderly people with or without cognitive decline to improve their physical fitness and metabolic profiles and mitigate cognitive decline with normal aging.”
List of newly added references
- Aagaard, P.; Suetta, C.; Caserotti, P.; Magnusson, S.P.; & Kjær, M. Role of the nervous system in sarcopenia and muscle atrophy with aging: strength training as a countermeasure. Scand J Med Sci Sports. 2010, 20(1), 49-64.
- Ribeiro, A.S.; Aguiar, A.F.; Schoenfeld, B.J.; Nunes, J.P.; Cavalcante, E.F.; Cadore, E.L.; Cyrino, E.S. Effects of different resistance training systems on muscular strength and hypertrophy in resistance-trained older women. J Strength Cond Res. 2018,32, 545-553.
- Liu, C.J.; Latham, N. Adverse events reported in progressive resistance strength training trials in older adults: 2 sides of a coin. Arch Phys Med Rehabil. 2010,91, 1471-1473.
- Orssatto, L.D.R.; Moura, B.D.; Bezerra, E.D.S.; Andersen, L.L.; Oliveira, S.D.; Diefenthaeler, F. Influence of strength training intensity on subsequent recovery in elderly. Exp Gerontol.2018, 106, 232-239.
- Colado, J.C.; Triplett, N.T. Effects of a short-term resistance program using elastic bands versus weight machines for sedentary middle-aged women. J Strength Cond Res. 2008, 22, 1441-1448.
- Melchiorri, G.; Rainoldi, A. Muscle fatigue induced by two different resistances: Elastic tubing versus weight machines. J Electromyogr Kinesiol.2011, 21, 954-959.
- Kwak, C.J.; Kim, Y.L.; Lee, S.M. Effects of elastic-band resistance exercise on balance, mobility and gait function, flexibility and fall efficacy in elderly people. J Phys Ther Sci. 2016, 28, 3189-3196.
- Stewart, K.J.; Bacher, A.C.; Turner, K.; Lim, J.G.; Hees, P.S.; Shapiro, E.P.; Tayback, M.; Ouyang, P. Exercise and risk factors associated with metabolic syndrome in older adults. Am J Prev Med. 2005, 28, 9-18.
- Mcleod, J.C.; Stokes, T.; Phillips, S.M. Resistance exercise training as a primary countermeasure to age-related chronic disease. Front Physiol. 2019,10, 645.
Patten, R.K.; Pascoe, M.C.; Moreno-Asso, A.; Boyle, R.A.; Stepto, N.K.; Parker, A.G. Effectiveness of exercise interventions on mental health and health-related quality of life in women with polycystic ovary syndrome: a systematic review. BMC Public Health 2021, 21(1), 2
Reviewer 2 Report
Comments to Authors:
1- Title is not clear, should be more specific about types of intervention, For example: combined exercise training.
2- You should include exercise training protocol in Abstract with more details.
3- There are different exercise training (aerobic and resistance, or both) on cognitive function. Why did you think this unchallenging exercise training for brain is effective for cognitive function? What are your hypothesis? In addition, low-load resistance training is suitable for improving cognitive function?
4- It seems that you could not explain why you chose this protocol.
5- What are your primary outcome and your secondary outcomes?
6- What is purpose of study?
Methods:
1- How did you estimate sample size? Any software?
2- How did you allocate subjects? What is your primary outcomes?
3-How did you assess in inclusion criteria cognition impairments?
4- Was MMSE sensitive enough?
5- Cardio-metabolic Risk factors NOT metabolic risk factors
6- Why did not use SPPB for evaluating function?
Results:
1- Graphs don’t have enough quality.
Author Response
Our Responses to Reviewer 2
We deeply appreciate the reviewers for their thoughtful comments. We did our best to address all the comments/critics point-by-point, which are highlighted in yellow color. Ten references are newly cited and listed on the last page.
Q1) Title is not clear, should be more specific about types of intervention, For example: combined exercise training.
ANS1) Thanks. In our response to the comment, we modified the title as follows; “A Non-Randomized Combined Program of Walking and Low-Load Resistance Exercise Improves Cognitive Function and Cardiometabolic Risk Factors in Community-Dwelling Elderly Women”.
Q2) You should include exercise training protocol in Abstract with more details.
ANS2) Thanks. The exercise program is explained in more detail as follows; “The exercise intervention consisted of 3 days of resistance exercise and 2 days of walking.”
Q3) There are different exercise training (aerobic and resistance, or both) on cognitive function. Why did you think this unchallenging exercise training for brain is effective for cognitive function? What are your hypothesis? In addition, low-load resistance training is suitable for improving cognitive function?
ANS3) Thanks for the critical comments. We believe that low-load and high-repetition resistance exercise is suitable and safer, and more effective considering our study participants (age, lack of previous experience, risk of injury, adherence to program, and others). In agreement, a recent study showed that low-load resistance exercise, but not high-load resistance exercise, improved cognitive function in older adults (Sardeli AV, et al. Low-load resistance exercise improves cognitive function in older adults. Revista Brasileira de Medicina do Esporte, 2018; 24(2): 125-129). They showed that high-load resistance exercise caused uncomfortable sensations or fatigue compared to low-load resistance exercise.
In our response to the comments, the Introduction is revised as follows (lines 54-61/page 2); “The lack of evidence about exercise interventions has multifactorial causes, including exercise intensity inadequate to promote aerobic fitness, poor exercise adherence, short study duration, low statistical power, and use of clinically irrelevant measures [12]. In addition, although there is a linear relationship between training load and an increase in muscle size and strength in older women [13], high-load resistance training often increases the risk of injury or overuse [14] and impairs post-exercise physical function [15] in elderly persons. Strength-naïve women may experience superior adherence to low-load elastic band training compared to stationary resistance training programs [16] and superior cognitive benefit to high-load resistance exercise [17]. Elastic band training provides more benefits compared to free-weight training, such as hindered injury risk and enhanced functional strength [18].”
In addition, the term “high-repetition” is added to emphasize the endurance type of resistance exercise as follows (lines 99-100/page 3); “The exercise intervention consisted of 3 days (i.e., Monday, Wednesday, and Friday) of low-load and high-repetition elastic band resistance exercise and 2 days (i.e., Tuesday and Thursday) of walking for 6 months under the supervision of certified exercise leaders.”
Q4) It seems that you could not explain why you chose this protocol.
ANS4) Thanks. This question appears to be the same in Q3. So please refer to our reply to question #3.
Q5) What are your primary outcome and your secondary outcomes?
ANS5) Thanks. The primary and secondary outcomes are indicated as follows (lines 111-112/page 4); “Additionally, a certified nurse trained in cognitive assessments conducted face-to-face interviews to measure the primary outcome of cognitive function and the secondary outcomes of depressive symptoms, functional physical capacity, and cardiometabolic risk factors.”
Q6) What is purpose of study?
ANS6) Thanks. In our response to the comment, the purpose is stated as follows (Lines 63-65/page 2); “This study aims to investigate the cognitive benefits of a long-term exercise intervention consisting of walking and low-load and high-repetition resistance exercise for elderly community-dwelling Korean adults.”
Methods:
Q7) How did you estimate sample size? Any software?
ANS7) Thanks. In our response to the comment, the relevant statement is revised as follows (lines 87-89/page 3); “The sample size of each group was calculated using the G*Power software (3.1.9.7; Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany) to detect a significant difference in the primary outcome of cognitive function between the control (n=25) and intervention (n=25) groups, with a statistical power of 85% and a probability of alpha error of 0.05.”
Q8) How did you allocate subjects? What is your primary outcomes (cognitive function assessed by MMSE)?
ANS8) Thanks. In our response to the comment, we stated as follows (lines 84-86/page 3 and lines 110/page 4); “Following the baseline measurements, all the participants were allocated to either the exercise intervention group (n = 30) or the control group (n = 30) based on their date of birth and preference.”
“Additionally, a certified nurse trained in cognitive assessments conducted face-to-face interviews to measure the primary outcome of cognitive function and the secondary outcomes of depressive symptoms, functional physical capacity, and cardiometabolic risk factors.”
Q9) How did you assess in inclusion criteria cognition impairments?
ANS9) Thanks. As mentioned in the Materials and Methods (“Participants and Study Design”), the presence of mental disorders was determined based on their physician’s health record.
Q10) Was MMSE sensitive enough?
ANS10) Thanks. Cognitive function was assessed using the Korean version of the Mini-mental State Examination (K-MMSE) optimized for screening dementia (MMSE-DS). The validity and reliability of the K-MMSE for cognitive function were reported previously (Park and Kwon, 1995,. Int J Geriatr Psychiatr., 5, 381-387).
Q11) Cardio-metabolic Risk factors NOT metabolic risk factors
ANS110 Thanks. As suggested, metabolic risk factors are renamed as Cardiometabolic risk factors throughout the text.
Q12) Why did not use SPPB for evaluating function?
ANS12) Thanks. In addition to the Short Physical Performance Battery (SPPB, the 30-s sit-to-stand test is a valid assessment tool for evaluating lower limb strength in older adults Rikli and Jones, 2013, Gerontologist, 53, 255-267), which was adopted in the KLoSA.
Results:
Q13) Graphs don’t have enough quality.
ANS13) Thanks. Figures are upgraded in 300 DPI.
List of newly added references
- Aagaard, P.; Suetta, C.; Caserotti, P.; Magnusson, S.P.; & Kjær, M. Role of the nervous system in sarcopenia and muscle atrophy with aging: strength training as a countermeasure. Scand J Med Sci Sports. 2010, 20(1), 49-64.
- Ribeiro, A.S.; Aguiar, A.F.; Schoenfeld, B.J.; Nunes, J.P.; Cavalcante, E.F.; Cadore, E.L.; Cyrino, E.S. Effects of different resistance training systems on muscular strength and hypertrophy in resistance-trained older women. J Strength Cond Res. 2018,32, 545-553.
- Liu, C.J.; Latham, N. Adverse events reported in progressive resistance strength training trials in older adults: 2 sides of a coin. Arch Phys Med Rehabil. 2010,91, 1471-1473.
- Orssatto, L.D.R.; Moura, B.D.; Bezerra, E.D.S.; Andersen, L.L.; Oliveira, S.D.; Diefenthaeler, F. Influence of strength training intensity on subsequent recovery in elderly. Exp Gerontol.2018, 106, 232-239.
- Colado, J.C.; Triplett, N.T. Effects of a short-term resistance program using elastic bands versus weight machines for sedentary middle-aged women. J Strength Cond Res. 2008, 22, 1441-1448.
- Melchiorri, G.; Rainoldi, A. Muscle fatigue induced by two different resistances: Elastic tubing versus weight machines. J Electromyogr Kinesiol.2011, 21, 954-959.
- Kwak, C.J.; Kim, Y.L.; Lee, S.M. Effects of elastic-band resistance exercise on balance, mobility and gait function, flexibility and fall efficacy in elderly people. J Phys Ther Sci. 2016, 28, 3189-3196.
- Stewart, K.J.; Bacher, A.C.; Turner, K.; Lim, J.G.; Hees, P.S.; Shapiro, E.P.; Tayback, M.; Ouyang, P. Exercise and risk factors associated with metabolic syndrome in older adults. Am J Prev Med. 2005, 28, 9-18.
- Mcleod, J.C.; Stokes, T.; Phillips, S.M. Resistance exercise training as a primary countermeasure to age-related chronic disease. Front Physiol. 2019,10, 645.
- Patten, R.K.; Pascoe, M.C.; Moreno-Asso, A.; Boyle, R.A.; Stepto, N.K.; Parker, A.G. Effectiveness of exercise interventions on mental health and health-related quality of life in women with polycystic ovary syndrome: a systematic review. BMC Public Health 2021, 21(1)
Reviewer 3 Report
I think it is an important topic to be disseminated, as it pertains to current trends in the health behaviors of older adults. However, certain issues need to be addressed.
1. The authors may consider the reporting guideline on reporting intervention evaluation studies using nonrandomized designs.
Des Jarlais DC, Lyles C, Crepaz N, Trend Group. Improving the reporting quality of nonrandomized evaluations of behavioral and public health interventions: the TREND statement. Am J Public Health. 2004;94(3):361-366.
2. The authors should provide more background and include all relevant references in the introduction and discussion section.
In the introduction, the authors wrote, “In contrast to numerous studies of patients with MCI or dementia, however, only a few evidence-based studies support the cognitive benefits of physical activity and exercise for healthy older adults. Most previous studies have focused on short-term effects and have not found that exercise intervention in older adults has cognitive benefits [8], although some long-term studies have found cognitive benefits [9].
As far as I know, there at least three more similar trials studied the affect of resistance training on healthy older adults:
Cassilhas RC, Viana VA, Grassmann V, Santos RT, Santos RF, Tufik S, et al. The impact of resistance exercise on the cognitive function of the elderly. Med Sci Sports Exerc. 2007;39:1401-7. [PMID: 17762374]
Lachman ME, Neupert SD, Bertrand R, Jette AM. The effects of strength training on memory in older adults. J Aging Phys Act. 2006; 14:59-73. [PMID: 16648652]
van de Rest O, van der Zwaluw NL, Tieland M, Adam JJ, Hiddink GJ, van Loon LJ, et al. Effect of resistance-type exercise training with or without protein supplementation on cognitive functioning in frail and pre-frail elderly: secondary analysis of a randomized, double-blind, placebo-controlled trial. Mech Ageing Dev. 2014;136-137:85- 93. [PMID: 24374288] doi:10.1016/j.mad.2013.12.005
The authors may consider including the comparison between this study and the previous studies, and adding more discussion on how this study adds to the existing evidence, which I believe will be more valuable for the audience.
Author Response
Our Responses to Reviewer 3
We deeply appreciate the reviewers for their thoughtful comments. We did our best to address all the comments/critics point-by-point, which are highlighted in yellow color. Ten references are newly cited and listed on the last page.
Q1) The authors may consider the reporting guideline on reporting intervention evaluation studies using nonrandomized designs. Des Jarlais DC, Lyles C, Crepaz N, Trend Group. Improving the reporting quality of nonrandomized evaluations of behavioral and public health interventions: the TREND statement. Am J Public Health. 2004;94(3):361-366.
ANS1) Thanks. In our response to the comments, we added the word “non-randomized” to the title, the abstract, and the study design. Inclusion and exclusion criteria, sample size calculation, group assignment method, non-blinded study design, and primary and secondary outcomes are clearly stated in the Materials and Methods section. Statistics are clearly stated. Results and Discussion are stated as suggested.
Q2) The authors should provide more background and include all relevant references in the introduction and discussion section.
ANS2) In the introduction, the authors wrote the Introduction (lines 50-65) as follows; “In contrast to numerous studies of patients with MCI or dementia, however, only a few evidence-based studies support the cognitive benefits of physical activity and exercise for healthy older adults. Most previous studies have focused on short-term effects and have not found that exercise intervention in older adults has cognitive benefits [8, 9], although some long-term studies have found cognitive benefits [10, 11].
The lack of evidence about exercise interventions has multifactorial causes, including exercise intensity inadequate to promote aerobic fitness, poor exercise adherence, short study duration, low statistical power, and use of clinically irrelevant measures [12]. In addition, although there is a linear relationship between training load and an increase in muscle size and strength in older women [13], high-load resistance training often increases the risk of injury or overuse [14] and impairs post-exercise physical function [15] in elderly persons. Strength-naïve women may experience superior adherence to low-load elastic band training compared to stationary resistance training programs [16] and superior cognitive benefit to high-load resistance exercise [17]. Elastic band training provides more benefits compared to free-weight training, such as hindered injury risk and enhanced functional strength [18].
Nonetheless, there is not enough evidence to say that the exercise interventions applicable to elderly people living independently in the community effectively delay or prevent cognitive decline with normal aging [8]. This study aims to investigate the cognitive benefits of a long-term exercise intervention consisting of walking and low-load and high-repetition resistance exercise for elderly community-dwelling Korean adults.”
Q3) As far as I know, there at least three more similar trials studied the affect of resistance training on healthy older adults. The authors may consider including the comparison between this study and the previous studies, and adding more discussion on how this study adds to the existing evidence, which I believe will be more valuable for the audience.
ANS3) Thanks for the suggestions. We cited two of the references (Cassilhas et al., 2006 and van de Rest et al., 2014) the reviewer suggested.
List of newly added references
- Aagaard, P.; Suetta, C.; Caserotti, P.; Magnusson, S.P.; & Kjær, M. Role of the nervous system in sarcopenia and muscle atrophy with aging: strength training as a countermeasure. Scand J Med Sci Sports. 2010, 20(1), 49-64.
- Ribeiro, A.S.; Aguiar, A.F.; Schoenfeld, B.J.; Nunes, J.P.; Cavalcante, E.F.; Cadore, E.L.; Cyrino, E.S. Effects of different resistance training systems on muscular strength and hypertrophy in resistance-trained older women. J Strength Cond Res. 2018,32, 545-553.
- Liu, C.J.; Latham, N. Adverse events reported in progressive resistance strength training trials in older adults: 2 sides of a coin. Arch Phys Med Rehabil. 2010,91, 1471-1473.
- Orssatto, L.D.R.; Moura, B.D.; Bezerra, E.D.S.; Andersen, L.L.; Oliveira, S.D.; Diefenthaeler, F. Influence of strength training intensity on subsequent recovery in elderly. Exp Gerontol.2018, 106, 232-239.
- Colado, J.C.; Triplett, N.T. Effects of a short-term resistance program using elastic bands versus weight machines for sedentary middle-aged women. J Strength Cond Res. 2008, 22, 1441-1448.
- Melchiorri, G.; Rainoldi, A. Muscle fatigue induced by two different resistances: Elastic tubing versus weight machines. J Electromyogr Kinesiol.2011, 21, 954-959.
- Kwak, C.J.; Kim, Y.L.; Lee, S.M. Effects of elastic-band resistance exercise on balance, mobility and gait function, flexibility and fall efficacy in elderly people. J Phys Ther Sci. 2016, 28, 3189-3196.
- Stewart, K.J.; Bacher, A.C.; Turner, K.; Lim, J.G.; Hees, P.S.; Shapiro, E.P.; Tayback, M.; Ouyang, P. Exercise and risk factors associated with metabolic syndrome in older adults. Am J Prev Med. 2005, 28, 9-18.
- Mcleod, J.C.; Stokes, T.; Phillips, S.M. Resistance exercise training as a primary countermeasure to age-related chronic disease. Front Physiol. 2019,10, 645.
- Patten, R.K.; Pascoe, M.C.; Moreno-Asso, A.; Boyle, R.A.; Stepto, N.K.; Parker, A.G. Effectiveness of exercise interventions on mental health and health-related quality of life in women with polycystic ovary syndrome: a systematic review. BMC Public Health 2021, 21(1), 2310.
