Elderly attention improvement after a physical aerobic exercise

Introduction. Decreasing cognitive performance is one of the main changes due to the aging process and physical exercise could be an effective intervention to minimize this reduction in cognitive impairment. Objective. to investigate the effects of physical aerobic exercise (dance class) on concentrated attention performance in the elderly. Method. Twenty-five elderly subjects (24 women) aged 68.5±6.7years, 65.0±11.3kg, and 149.1±6.25cm participated in this study. To evaluate effects of physical aerobic exercise on concentrated attention performance, the Toulouse-Piéron Attention Test (attentional speed, attention accuracy, and attentional fatigue resistance) was applied before and after a single physical aerobic exercise (dance class) with participants. Student's paired t-test was performed to compare attentional performance before and after physical exercise. Results. After physical exercise, there was an improvement in attentional speed (84.0±36.3 vs. 109.4±37.8; p<0.05), attentional accuracy (4.8±5.7 vs. 2.5±1.9; p<0.05) and attentional fatigue resistance (-154.6±95.5 vs. -103.7±98.9; p<0.05) in the elderly subjects. Conclusion : A single session of physical aerobic exercise of dance class improved concentrated attention performance in the elderly, which could improve concentration and activity performance in their daily lives.


INTRODUCTION
Aging is a human natural process leading to biological and psychological changes 1 and cognitive impairment is one of the main changes observed 2 . Cognition understands all phases of the information process, such as attention, perception, memory, reasoning, problem-solving, and learning and psychomotor ability (reaction time, movement speed and performance) 3 .
Attention is a relevant cognitive variable that allows correct stimulus perception and information processing 4 enabling the identification and memorizing of environment stimulus 5 . Therefore, attentional impairment due to the aging process could influence daily activity management -such as preparing meals, taking medications, shopping, self-care of health-related problems -and could lead to a reduction in the quality of life and limit social life in the elderly 1 .
Despite an attentional and cognitive ability decrease due to the aging process, a single physical aerobic exercise bout at moderate intensity may improve cognitive performance functions, such as selective attention, processing speed, and short-term memory 6,7 . Therefore, physical exercise can improve attention and allow any task to be performed more independently, besides having a positive effect on functional capacity 1 . The cognitive function improvement due to physical exercise can be attributed to cerebral blood and nutrients flow increase, and a rise in neurotransmitter activity 8,9 , improving brain function, increasing neural metabolism and cerebral functionality, and improving cognitive performance 10 . The magnitude of cognitive responses to physical exercise depends on the nature of the task (type of cognitive task) and characteristics of the physical exercise bout 3 .
Several studies have demonstrated the beneficial effects of physical exercise on attention in children, young adults, and elderly after an aerobic exercise bout, which improved selective attention 11 , sustained attention 12 , divided attention 11 and the visual attention of the elderly 13 . However, information about physical exercise bouts and concentrated attention (the ability to select a source of information at a given time and keep the focus on that target stimulus) in the elderly is limited 14 . Improvement of concentrated attention was observed in young adults due to a multimodal exercise bout (stretching, strength, balance and coordination exercise and walking) 15 and in elderly subjects due to a chronic response to a circuit training 16 and aerobic training 17,18 . Therefore, physical exercise seems to improve concentrated attention in young adults due to a single exercise bout, and in the elderly population due to a chronic physical training response. However, we did not find any paper that investigated the effects of an acute aerobic exercise bout on concentrated attention in elderly people.
Although the aging process may influence cognition and exercise responses, an improvement in concentrated attention could be expected after a single bout of aerobic exercise in elderly subjects. The aim of study was to investigate the effects of a single aerobic exercise bout on concentrated attention in the elderly.

METHOD
Twenty-five elderly subjects ( Each volunteer was invited to participate, and all procedures were carried out in accordance with the ethics council. All participants were elderly (>60 years old), had good visual acuity (with or without aid of glasses) and had the ability to respond to the protocols used.

Experimental Design
To evaluate the effect of physical exercise on concentrated attention, the Toulouse-Piéron Attention test 19,20 was applied immediately before and after an exercise bout.
Initially, a physical screen was performed, and body

Physical exercise protocol
The physical exercise protocol was set as an aerobic exercise bout of 60 min and composed of a warm-up (5 min), collective dance class (50 min), and a cold down activity (5 min). Heart rate was continuously monitored by a bluetooth heart rate chest monitor (Polar H10, Finland) and Polar Beat app and exercise intensity was calculated through the percentual of maximum heart rate calculated by the ratio of mean exercise heart rate and maximum heart rate estimated 21 . The mean exercise intensity of exercise protocol was 63.8±9.4% of maximum heart rate. Attentional test was performed immediately before and after the exercise protocol.

Statistical analysis
All data were tested to normal distribution (Shapiro-Wilk test) and homoscedasticity (Levene test). To compare concentrated attention before and after the exercise bout, a paired Student's t-test was performed. All results are presented as mean ± standard deviation and a significance level of p<0.05 was set. Sigma Plot (14) was used to analyze all data.

RESULTS
After the physical exercise session, an increase in the number of correctly marked symbols (attentional speed) was observed from 84.0±36.3 to 109.4±37.8 (p<0.05; Figure 1).
The accuracy and attentional fatigue resistance index reduced after the exercise bout, indicating an improvement in ability to concentrate attention (4.8±5.7 vs. 2.5±1.9; p<0.05; Figure 2), and on-task test performance (-154.6±95.5 vs. 103.7±98.9, p<0.05; Figure 3).   Moreover, attentional improvements may be associated with increased excitation levels of the central nervous system, due to the higher concentration of brain catecholamines, βendorphin and dopamine 25 related to the increase in catecholamine concentration during physical exercise and greater permeability of the blood-brain barrier 26 , allowing a high passage of these neurotransmitters to the brain. All these responses could lead to an increase in prefrontal brain activity and in executive functions, such as attention 27 .
Previous electroencephalogram studies suggest that physical exercise increases brain activity, decreasing the time it takes to perceive, identify, and respond to a stimulus 28