European Journal of Cardiovascular Medicine

The hand is one of the most versatile and complicated organs of the human body. It gives us the ability to perform a wide variety of tasks ranging from simple activities like grasping objects and stacking blocks to more complex tasks such as playing musical instruments and performing a highly precise surgery. The ability to perform such precise, diverse and flexible movements to grasp and manipulate objects is known as manual dexterity, which is also referred to as fine motor skills^1,2. It involves muscular, skeletal, and neurological functions to produce small, precise movements. Fine motor skills are a fundamental component of one's day to day life and any impairment in one's fine motor ability will lead to a reduced quality of life, therefore making it important to find ways to improve our fine motor performance.

Yoga is a 3,000-year-old tradition that has gained popularity as a form of complementary and alternative medicine in the past³. It is a form of mind-body practice that comprises 8 limbs known as Ashtanga, aiming to unite the mind, body and spirit⁴. Hatha Yoga is one of the most commonly practised forms of yoga in the world, consisting of physical postures (asanas) and breathing practices (pranayama) and meditation⁵. It offers several benefits such as improved physical, mental, intellectual and spiritual health, while also acting as an effective method of managing and reducing stress, anxiety and depression⁶. It also influences motor functioning, such as static motor performance and tweezer dexterity^7,8,9. The yoga technique used in this study was pranayama, which consists of focused and controlled breathing practices. Pranayama has shown to improve Purdue pegboard scores in individuals with hypertension¹⁰. It has also shown to improve finger dexterity and visual discrimination¹¹. 

Cardiovascular exercise, more commonly known as ‘cardio’ and ‘aerobic exercise', is a type of exercise that is maintained by the oxygen delivered to the muscles via blood. It is usually low to moderate in intensity and is generally practised for sustained periods of time¹²,¹³. There are several forms of aerobic exercise such as walking, jogging, running, cycling, skipping and many more. It is one of the most popular forms of exercise providing a wide variety of benefits such as weight control, improved endurance, improved cardiovascular functioning, glycaemic control, reduced cholesterol levels and improved mental health^12,13,14. Studies have shown that aerobic exercise influences fine motor functioning of healthy subjects and subjects with coronary artery disease^15,16. Practising high intensity aerobic exercise over an extended duration has also shown to improve bimanual dexterity task performance in patients with Parkinson’s disease¹⁷.   

There are a limited number of studies assessing the immediate effects of Pranayama and Aerobic exercise on fine motor skills, and no studies comparing their effects as per the review of literature conducted by the authors. Given the popularity of these practices and the vital role that fine motor skills play in one’s daily life, it is essential to find ways to improve fine motor functioning. Hence, the objectives of this study were (i) to assess the effects of pranayama on the fine motor skills of healthy young adults, (ii) to assess the effects of aerobic exercise on the fine motor skills of healthy young adults, (iii) to compare the individual effects of pranayama and aerobic exercise on fine motor skills of healthy young adults.

Participants and Study Design

Sixty healthy volunteers were recruited from a medical college in Bengaluru with the following inclusion criteria: 1) volunteers aged between 18-24 years; 2) No history of acute or chronic diseases; 3) No smoking history. The participants were informed of the purpose and risks of the study and signed the informed consent. The sample size was estimated using G*Power v3.1.9.7 software. Allowing a type 1 error of 5% (α = 0.05), the required sample size to detect a conventional large effect size of 0.8 (d = 0.8) with a power of 85% (1-b=0.85) in an Independent samples t-test comparing the improvement in motor performance between 2 groups, was calculated to be 60, with 30 participants per group¹⁸.

The participants were equally divided into 2 groups – Pranayama Group (PG) (n=30) and Exercise Group (EG) (n=30). The two study groups were perfectly matched (chi-square test, p=1.00) in sex distribution with each group having 11 (36.7%) female participants and 19 (63.3%) male participants. The mean age of participants (in years) was 19.5 ± 0.9 [19.2, 19.9] for EG and 19.7 ± 0.844 [19.4, 20] for PG. The groups were matched by age, as confirmed by Mann-Whitney U test (p=0.561) (Shapiro-Wilk test, p<0.001 for both EG and PG).    

Assessment

All participants were assessed using the O'Connor Tweezer Dexterity Test two times in total, i) before intervention {Baseline/pre-test score}, ii) after intervention {post-test score}

O'Connor Tweezer Dexterity Test

It consists of a 5 7/8" × 11 5/8" board. Located in the upper half of the board is a pin well measuring 4 ¾" in diameter arranged in 10 rows of 10 holes each spaced ½" apart. Into these holes, the subject can insert one pin 1" long and 1/16" in diameter (100 pins in total). This test measures the speed with which the subject using tweezers can pick up pins one at a time and place them in small holes on a metal plate. The pins must be placed in an orderly fashion with the subject filling the next row only after filling the previous one.

The participants should be seated comfortably at the table. The Tweezer Dexterity test is placed on the table before the subject, with the tray on the side of the dominant hand. It should be at an angle of about 90 degrees with the subject's working hand but may be changed if desired. The time taken to place all 100 pins is recorded, with the timer starting after the first pin is placed and the timer ending when the final pin is placed. A lower time indicates better fine motor performance¹⁹. The participants completed a trial attempt of the test after which their baseline readings were taken.

Intervention

The Pranayama Group (PG) was made to perform Anulom Vilom pranayama for 10 minutes in a balanced meditative posture. Pranayama begins with the participant fully exhaling through both nostrils. Then, using the thumb, the left nostril is closed, and a slow and deep inhalation is taken through the right nostril. The participant then closes both the nostrils and holds their breath for a few seconds before releasing the thumb and opening the left nostril. The participant must then slowly exhale through the open nostril. To complete the cycle the participant must repeat the same on the opposite side: inhale through the open left nostril, hold their breath by closing both nostrils, and exhale through the right nostril. This completes one full cycle, which is repeated over 10 minutes. The Exercise Group (EG) will perform 15 minutes of brisk walking such that their heart rate reaches 50% of their target heart rate (target heart rate = 220-age). After the intervention, the participants' fine motor performance will be assessed using the O'Connor Tweezer Dexterity Test.

Data Analysis

Statistical analysis was done using Jamovi software. Descriptive statistics were analysed using frequencies for categorical variables; and mean, median, and standard deviation for continuous variables, expressed as mean ± standard deviation and 95% confidence intervals [lower limit, upper limit]. Chi-square test of association was used to analyse categorical variables. Normality of continuous variables was tested using the Shapiro-Wilk test. ANOVA was used to analyse the overall within-subjects and between-subjects effects and interactions. Independent and paired student t-tests were used to pairwise compare the means of the continuous variables. Mann-Whitney U test and Wilcoxon W tests were used for variables that were not normally distributed.

Descriptive Analysis

Table 1 Descriptive Statistics

A total of 60 participants were equally divided into 2 groups – Pranayama Group (PG) (n=30) and Exercise Group (EG) (n=30). The two study groups were perfectly matched (chi-square test, p=1.00) in sex distribution with each group having 11 (36.7%) female participants and 19 (63.3%) male participants. The mean age of participants (in years) was 19.5 ± 0.9 [19.2, 19.9] for EG and 19.7 ± 0.844 [19.4, 20] for PG. The groups were matched by age, as confirmed by Mann-Whitney U test (p=0.561) (Shapiro-Wilk test, p<0.001 for both EG and PG). The mean pre-test scores (in seconds) were 408.7 ± 49.992 [390, 427.4] for EG and 447.4 ± 70.623 [421, 473.7] for PG. The mean post-test scores (in seconds) were 368.2 ± 45.156 [351.3, 385] for EG and 379.2 ± 48.17 [361.2, 397.2] for PG. The mean improvements in test performance (in seconds), computed as the difference between pre-test and post-test scores (Pre-test score – Post-test score), were 40.5 ± 21.963 [32.3, 48.7] for EG and 68.2 ± 31.485 [56.4, 79.9] for PG. (Table 1)

Overall Main and Interaction Effects

Repeated Measures ANOVA was performed with within-subjects repeated measures factor being time (pre-test and post-test) and between-subjects factor being group (EG or PG). The main effect of time was significant (F=240.5, p<0.001) indicating that the overall post-test scores were significantly different from the pre-test scores for all participants (Table 2). The main effect of group showed no significance (F=3.33, p=0.073) indicating that averaged over all pre-test and post-test scores, there was no difference between the groups (Table 3). There was also a significant overall interaction effect observed between time and group (F=15.6, p<0.001) indicating that the improvement between pre-test and post-test scores were significantly different between the groups, one being more than the other (Table 2). Figure 1 visualizes the interaction effect in the form of non-parallel time series lines for the two groups, with PG’s line being steeper than EG’s line.

Figure 1 Comparison of mean test scores and the interaction effect between time and group

Table 2 Within-Subjects Effects

Table 3 Between-Subjects Effects

Within-Group Comparisons

A significant improvement of 38.2 [31.8, 47.0] seconds was detected in EG between mean pre-test and post-test scores (Wilcoxon W, p<0.001) (Figure 2). A larger significant improvement of 68.2 [56.4, 79.9] seconds was detected in PG (Student’s t, p<0.001) (Figure 3). This suggests that both interventions of exercise and pranayama led to a significant improvement in the participants’ performance in completing the motor task (Table 4).

Figure 2 and 3 Within-group comparison between mean pre-test and post-test scores in EG (left) and PG (right)

Table 4 Within-group comparisons (Pre-test – Post-test)

Between-Group Comparisons

A significant difference was detected in the mean pre-test scores of the two groups with that of PG being 38.7 [7.03, 70.3] seconds higher than that of EG (Student’s t, p=0.017) (Figure 4). However, the mean post-test scores showed only a smaller non-significant difference of 11.0 [-13.12, 35.1] seconds between the two groups (Student’s t, p=0.365) (Figure 5). On examining the mean improvements between the two groups, it was observed that PG showed a significant 26.0 [14.68, 40.0] seconds more improvement than EG (Mann-Whitney U test, p<0.001), thus confirming the ANOVA findings of the significant interaction effect between time and group (Figure 6). This suggests that although PG started off worse than EG with high pre-test scores, pranayama caused a larger improvement in the participants’ performance as compared to exercise, thereby bringing their post-test scores to the same level (Table 5)    

Figure 4 and 5 Between-group comparison of mean pre-test (left) and post-test (right) score

Figure 6 Between-group comparison of mean improvement in test scores

Table 5 Between-group comparisons (Pranayama – Exercise)

In the present study, there was a significant improvement in fine motor performance immediately following Pranayama and Aerobic exercise.

The improvement in fine motor performance following pranayama, as seen in the results of the present study, can be explained because of pranayama on one’s attention²⁰. Pranayama also helps in reducing anxiety, which in turn positively influences fine motor performance^21,22. However, the anxiety of the participants in the present study were not assessed. A possible explanation as to how pranayama influences attention, could be the coupling of respiration and attention with the Locus Coeruleus playing a central role in the coupling, thereby increasing attention following pranayama²⁰. The Locus Coeruleus (LC) is a chemosensitive nucleus located in the brainstem that synthesises noradrenaline and hence regulates cortical arousal, attention and influences respiration. Since it is sensitive to CO2 levels, the fluctuations in CO2 levels during breathing exercises such as pranayama influences the activity of the LC’s thereby creating a link between attention and respiration. This enhanced activity of the LC leads to increased attention. A study conducted by Marie Brossard-Racine et al on children newly diagnosed with attention deficit hyperactivity disorder (ADHD), showed that they have more handwriting difficulties and motor impairments compared to children without ADHD²³. Another study conducted by Alexandra C Fietsam et al on young adults with and without ADHD, showed that participants without ADHD performed better in the Purdue Pegboard Test compared to the participants with ADHD²⁴. These studies show that attention influences fine motor performance.

A study conducted by Feray Soyupek et al, showing the immediate effect of aerobic exercise on dexterity of 40 patients with coronary artery disease, suggests that improvement in motor task following aerobic exercise could be due to increase in body temperature because of exercise¹⁶. A study conducted by Hee-Soon Woo showed that hand dexterity improved on exposure to warmer temperatures, suggesting that temperature influences fine motor performance²⁵. The study conducted by Feray Soyupek et al also suggests that catecholamines released during exercise positively influences dexterity¹⁶. However a study conducted by Kasper Skriver had contradictory findings, where there was no significant correlation between motor skill acquisition and catecholamine concentration²⁶. Interestingly there was a consistent correlation between plasma lactate levels and motor skill acquisition. Another possible explanation for the effect of aerobic exercise on fine motor performance can be due to improved cerebral blood flow as suggested by a study conducted by Lena Hübner et al¹⁵. The exact mechanism underlying the improvement in fine motor performance following cardiovascular exercise is unclear. Additional research is needed to clarify these processes and enhance our understanding of how cardiovascular exercise affects fine motor skills.  

The result of the present study demonstrates that both Pranayama and Cardiovascular Exercise are effective in improving fine motor performance. However, the improvement seen is greater in participants that have practised Pranayama.

As per the authors’ review of literature, this is the first study that compares the immediate effects of pranayama and cardiovascular exercise on motor skills of healthy young adults. The participants in the intervention groups were age and gender matched to ensure consistency between the two groups. The participants were given a practice attempt of the O’Connor tweezer dexterity test prior to recording baseline readings. This was done to minimise the influence of the practice effect. The inclusion of a control group could have minimised the influence of the practice effect. However, this study was conducted without a control group. The participants were aware that they were being timed during the test, but their timings were not revealed until their post intervention readings were taken. However, knowing that the test was being timed and that a faster time indicated a better result may have influenced participants to perform faster during the post intervention readings.

Acknowledgement

We would like to thank the department of physiology, Bangalore Medical College and Research Institute for their support and cooperation. We would like to thank the volunteers for their cooperation during the study. We would also like to thank Dr Suraj R S for his support in the statistical analysis of the data.

To summarise, a single short session of Pranayama or Cardiovascular Exercise can be practised for an immediate improvement in fine motor skills, with pranayama showing a greater improvement in comparison to cardiovascular exercise. Both activities can be performed in small spaces without any equipment making it easy and accessible to anyone. As discussed above there are many possible explanations as to why pranayama and cardiovascular exercise improve fine motor performance, but the exact mechanism is still unclear and further research needs to be done to deepen our understanding of this subject.

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