The Egyptian Heart Journal 70 (2018) 283–285

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The Egyptian Heart Journal

journal homepage: www.elsevier.com/locate/ehj

Original Article

Effect of exercise training on heart rate recovery in patients post anterior

myocardial infarction
Ahmed Elshazly ⇑, Hazem Khorshid, Hany Hanna, Ammar Ali
Department of Cardiology, Ain Shams University, Cairo, Egypt

a r t i c l e i n f o a b s t r a c t

Article history: Background: Regular exercise training has been shown to reduce mortality, improve functional capacity;
Received 20 March 2018 and control the risk factors in myocardial infarction (MI) patients. Heart rate recovery (HRR) is a strong
Accepted 21 April 2018 independent mortality predictor in patients with previous MI.
Available online 31 May 2018
Aim: The main objective of this study was to investigate the impact of exercise training on heart rate
recovery in patients post anterior myocardial infarction.
Keywords: Methods: We recruited patients one month after having anterior MI who were referred to cardiac
Heart rate recovery
rehabilitation (CR) clinic in Ain Shams University hospital between October 2016 and July 2017.
Exercise training
Myocardial infarction
All the patients participated in exercise training sessions 3 times a week for 12 weeks. Symptom limited
treadmill exercise test was done before and after exercise training program to calculate heart rate
recovery in 1st minute (HRR1) and 2nd minute (HRR2).
Results: A total of 50 patients, including 44 (88%) males, completed the exercise training program. The
mean age was 51 years. Statistically significant improvement in HRR1 and HRR2 was observed
(p value <0.001) after completion of exercise based cardiac rehabilitation program. Significant improve-
ment in resting heart rate was also observed (p value <0.001). Moreover, metabolic equivalent (METs)
and HR reserve were improved significantly (p value <0.001). No statistically significant changes were
observed in resting systolic and diastolic blood pressures and maximum HR (p value = 0.95, 0.76 and
0.31 respectively).
Conclusion: Exercise training improves HRR, resting HR, METs and HR reserve in post anterior MI
patients.
Ó 2018 Egyptian Society of Cardiology. Production and hosting by Elsevier B.V. This is an open access
article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction (HR) during exercise and recovery is controlled by the balance

between sympathetic and parasympathetic activity. Reduced
The heart rate is an important prognostic factor of cardiovascu- parasympathetic activity is thought to be responsible for attenu-
lar disease (CVD); as the heart rate is a significant indicator of ated HRR after exercise.3 A decreased HRR in first minute after
myocardial oxygen demand, individuals with a resting heart rate graded exercise is considered a powerful predictor of overall mor-
of more than 90 beats per minute (bpm) were found in several tality in patients with and without heart disease, independent of
studies to have a threefold increased mortality risk compared to workload, the presence or absence of myocardial perfusion defects,
those with a rate lower than 60 bpm.1 and changes in heart rate during exercise.4
Heart rate recovery (HRR) is defined as the difference between Hence the aim of the present study was to evaluate the effect of
peak HR during exercise and exactly 1 min or 2 min into the recov- exercise training based cardiac rehabilitation (CR) on heart rate
ery period after exercise. A HRR value less than 12 beats/min or recovery in patients post anterior myocardial infarction.
less than 22 beats/min at 1 and 2 min into the recovery period
respectively was found abnormal.2 2. Material and methods
The heart rate is regulated and determined predominantly by
the autonomic nervous system function. The change in heart rate The study included 50 patients one month after having anterior
MI who were referred to cardiac rehabilitation (CR) unit in Ain
Peer review under responsibility of Egyptian Society of Cardiology. Shams University hospital between October 2016 and July 2017.
⇑ Corresponding author. All patients were subjected to formal cardiac rehabilitation
E-mail address: dr_ahmdelshazly@med.asu.edu.eg (A. Elshazly). program including medical evaluation, risk factor modification,

https://doi.org/10.1016/j.ehj.2018.04.007
1110-2608/Ó 2018 Egyptian Society of Cardiology. Production and hosting by Elsevier B.V.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
284 A. Elshazly et al. / The Egyptian Heart Journal 70 (2018) 283–285

psychosocial management, nutritional counseling, physical activity disease, malignancy, patients with incomplete coronary revascu-
counseling and treadmill exercise training. Moderate intensity larization and residual ischemic symptoms as well as those who
exercise training 3 times a week for 12 weeks was prescribed refused to participate in the study were excluded from the sudy.
achieving target heart rate of 40–60% of HR reserve calculated from Data were analyzed using Statistical Program for Social Science
pre-exercise symptom limited stress test by modified Bruce proto- (SPSS) version 20.0. Quantitative data were expressed as mean ±
col. Each session was 30 min in duration. The exercise sessions standard deviation (SD). Qualitative data were expressed as fre-
were initiated with 5 min of warm-up exercise such as walking quency and percentage.
and stretching, followed by treadmill walking supervised by a
nurse and one of our study team. The procedures were explained 3. Theory
to the participants and informed written consent was obtained.
The Borg scale of rate of perceived exertion (RPE) was used to fol- Since exercise training helps to improve autonomic nervous sys-
low up the progression of exercise intensity where the patients tem function and increase parasympathetic activity, we designed
were exercised at an RPE of 11–13 in the absence of symptoms. this study to investigate the impact of exercise training on heart
Patient monitoring included rating of perceived exertion (RPE), rate recovery in patients post anterior myocardial infarction.
continuous ECG monitoring, recording of heart rate, blood pressure
and symptoms pre and post activity.
4. Results
In order not to affect the results of the study, patients on beta
blockers or other rate-reducing drugs continued using the same
A total of 50 patients completed the exercise training program.
doses during the study period. The participants were asked regard-
The baseline Demographic data, ejection fraction and risk factors
ing previous diagnoses of DM, hypertension, smoking, dyslipi-
are shown in Table 1.
demia and family history of premature ischemic heart disease.
In addition, resting heart rate, maximum heart rate, heart rate
All patients had full history and thorough physical examination,
reserve, heart rate recovery 1st minute (HRR1), heart rate recovery
Echocardiography to evaluate left ventricular ejection fraction by
2nd minute (HRR2), metabolic equivalent (METs), resting and peak
2D biplane Simpson’s methods.
exercise systolic and diastolic blood pressures of the study group
All participants performed symptom limited exercise treadmill
before and after exercise training program are included in Table 2.
test with modified Bruce protocol before and after implementing
There was statistically significant increase in (HRR1) and (HRR2)
exercise training program. In order to calculate HRR, the maximum
after exercise training program (18 ± 8.47 vs. 24.70 ± 7.57, p-value
heart rate during the exercise test was recorded. At the end of the
<0.001) and (30.52 ± 8.62 vs. 38.86 ± 10.13, p-value <0.001) respec-
exercise test the patients were asked to sit down without having a
tively. Also There was a statistically significant increase in HR
cooldown period and their heart rate was recorded again after 1
reserve (58.08 ± 20.50 to 65 ± 16.38, p-value <0.001). Moreover,
and 2 min into the recovery phase. The difference between maxi-
there was significant decrease in resting HR after the exercise train-
mum heart rate and these 2 recovery period measurements was
ing program (76.20 ± 14.21 to 68.16 ± 8.39, p-value <0.001).
considered HRR1 and HRR2 respectively. Patients with decompen-
Regarding maximum HR, resting systolic and diastolic blood pres-
sated heart failure, musculoskeletal disease interfering with the
sures there were no statistically significant changes (134 ± 19.83
planned exercise training, advanced kidney disease, advanced liver
to 131.84 ± 16.42, p-value 0.316), (113 ± 13.98 to 112.90 ± 13.67,
Table 1 p-value 0.955) and (70.30 ± 10.22 to 70.80 ± 8.83, p-value 0.765)
Demographic data, ejection fraction and risk factors. respectively.
Characteristic Total (N = 50)
Female 6 (12%)
5. Discussion
Male 44 (88%)
Age (years) [Range – Mean ± SD] 33–63 [51.50 ± 7.46] The benefits of exercise-based CR on cardiovascular risk factors,
Smoking 34 (68%) exercise tolerance, cardiac morbidity and mortality have been
HTN 19 (38%)
widely established in CAD patients 5.Our study showed statistically
DM 8 (16%)
Dyslipidemia 6 (12%) significant increase in mean HR recovery in 1st min (HRR1) and
Family history of premature IHD 8 (16%) 2nd minute (HRR2) after exercise training program (18 ± 8.47 vs.
EF% 24.70 ± 7.57, p-value <0.001) and (30.52 ± 8.62 vs. 38.86 ± 10.13,
<50% 37 (74%) p-value <0.001) respectively.
50% 13 (26%)
Range [Mean ± SD] 33–72 [44.32 ± 10.53]
These improvements in HR recovery was supported by Hai et al.
who investigated the effect of change in HR recovery after exercise

Table 2
Resting heart rate, maximum heart rate, heart rate reserve, heart rate recovery 1st minute (HRR1), heart rate recovery 2nd minute (HRR2), metabolic equivalent (METs), resting
and peak exercise systolic and diastolic blood pressures of the study group before and after exercise training program.

Before CR After CR Mean Diff. p-value

Resting Heart rate 76.20 ± 14.21 68.16 ± 8.39 8.040 <0.001
Maximum Heart rate 134.22 ± 19.83 131.84 ± 16.42 2.380 0.316
Heart rate reserve (maximum HR-Resting HR) 58.08 ± 20.50 65.68 ± 16.38 7.6 <0.001
Heart rate recovery in 1st min 18.00 ± 8.47 24.7 ± 7.57 6.70 (37%) <0.001
Heart rate recovery in 2nd min 30.52 ± 8.62 38.86 ± 10.13 8.34 (27%) <0.001
Metabolic equivalent 7.16 ± 1.13 7.92 ± 0.78 0.760 <0.001
Resting blood pressure
Systolic 113.02 ± 13.98 112.90 ± 13.67 0.120 0.955
Diastolic 70.30 ± 10.22 70.80 ± 8.83 0.500 0.765
Peak exercise blood pressure
Systolic 135.30 ± 18.33 134.90 ± 16.80 0.400 0.893
Diastolic 84.90 ± 11.54 78.40 ± 9.87 6.500 0.003
 A. Elshazly et al. / The Egyptian Heart Journal 70 (2018) 283–285 285

training on clinical outcomes in MI patients.6 The study included <0.001), our results are similar to the significant improvement in
386 consecutive patients with recent MI who were enrolled into exercise capacity found by Rebecca et al. who retrospectively
CR program. All patients underwent symptom-limited treadmill reviewed data from 458 patients enrolled in cardiac rehabilitation
testing at baseline and after exercise training and were prospec- and exercise programs after major cardiac event.11 At baseline (6
tively followed up in the outpatient clinic. Treadmill testing weeks after the cardiac event and before rehabilitation), exercise
revealed significant improvement in HRR after 8 weeks of exercise capacity ( 9%, p = 0.08) after cardiac rehabilitation and exercise
training (17.5 ± 10.0 to 19 ± 12.3, p-value = 0.011). training, had significant improvements in exercise capacity
Another study agreed with our results was done by Francesco (+40%, p < 0.001).
et al. who recorded the effect of exercise based CR on HR recovery
1st min in elderly patients after MI.7 This was a prospective obser- 6. Conclusion
vational study including 268 older patients after MI (217 men, 51
women), subdivided in two groups. Group A (N = 104) enrolled in The present study showed that 3 sessions of exercise training /
an exercise training program and Group B (N = 164) discharged week for 3 months is sufficient to obtain improvement in HR
with generic instructions to continue physical activity. At baseline recovery, resting HR and HR reserve. Moreover, improving exercise
and at 3 months follow up, all group A and group B patients under- capacity.
went an exercise testing. After completion of the exercise training
program, an improvement in HR recovery was observed in group A 7. Limitations of the study
(13.5 ± 3.7 to 18.7 ± 3.5, p-value <0.001). No changes in HRR were
observed in group B patients. 1. Small number of patients.
The positive effect of exercise training on autonomic nervous 2. Shorter duration of follow up (longer follow up for cardiac
system in supported also by Ribeiro et al.8. He conducted prospec- events will give strength to the present research).
tive randomized clinical trial on 38 patients after their first MI in
order to assess the effect of cardiac rehabilitation on the autonomic
8. Funding sources
function. Patients were randomized into two groups: exercise
training or control. The exercise group participated in an 8 weeks
This research did not receive any specific grant from funding
of exercise training, while the control group received standard
agencies in the public, commercial, or not-for-profit sectors.
medical care and follow up. The exercise training group showed
a significant decline in the systolic BP, decreased resting HR and
increase in HR recovery 1st min. Conflict of interest
Additionally, our study showed significant decrease in resting HR
after the exercise training program (76.20 ± 14.21 to 68.16 ± 8.39, None
p-value <0.001). These results were similar to Tsai et al.’s findings
who investigated the effects of CR on HR recovery 1 min and resting
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