Cardiovascular Journal of Africa: Vol 31 No 3 (May/June 2020)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 3, May/June 2020

118

AFRICA

individuals enrolled in regular AE (

20), of whom the arterial

baseline pressures of 10 were evaluated for 24 hours after 48

hours of rest after their last exercise training; and in the other 10

subjects the PEH induced by an AE session was assessed. The

other 20 individuals enrolled in regular LE were randomised and

evaluated in the same way (Fig. 1).

Body mass was measured with a digital scale having a capacity

of 150 kg and an accuracy of 100 g (EKS

SUPER 9805). Height

measurement was performed with a compact stadiometer fixed

to the wall, and with a range of 0 to 2.0 m and an accuracy of

1 mm (Coats Corrente

BA1010).

The heart rate (HR) was measured in both groups at rest and

after a cardiopulmonary test. For this a cardiac monitor (Polar

model FT1) was used to collect resting HR. The HR recording

was made in the seated position for two minutes after a rest of

10 minutes; the lowest HR reached in this period was used. The

maximal HR was measured immediately after completion of the

cardiopulmonary test.

For evaluation of the maximum aerobic capacity (VO

max

), the

progressive treadmill test was applied following the Balke–Ware

protocol.

The maximal VO

was evaluated using an open-

circuit spirometry VO2000

ventilometer and an Inbramed

treadmill.

35,36

BP was measured at rest and after cardiopulmonary tests in

both groups. For the former, the BP was assessed three times

after 10 minutes of rest in a seated position at intervals of one

minute, and the result was taken as the mean value, while for

the latter, the BP was assessed immediately after completion of

the treadmill test with a stethoscope (Missouri

) and a manual

aneroid sphygmomanometer (Missouri

) with a precision of

2 mmHg.

The ABPM was started 48 hours after the last training

session to evaluate the baseline BP in the AE and LE groups.

To evaluate PEH, the ABPM was started immediately after

the exercise session. Three devices of the Meditech KFT

brand, model ABPM-04, were used. The BP cuff was worn on

the non-dominant arm. Subjects were instructed to maintain

their customary daily activities, not to exercise, and to relax

and unbend the arm during the recording interval for daytime

ABPM. ABPM data were accepted with more than 75% of the

measurements effectively taken. Individual BP measurements

were revised for missing and erroneous values.

For comparison purposes, data were distributed across

the waking period, which consisted of the mean BP of the

measurement made every 15 minutes during the periods of

the day when the individual was awake (07:00 to 23:00), and

the sleep period, during which the BP was measured every 30

minutes and the mean value taken when the individual was

asleep (23:00 to 07:00). The result for each hour was then the

average of the values recorded during that hour.

For the AE-PEH, each individual remained at rest in a seated

position for 15 minutes, then BP was measured three times with

a sphygmomanometer and stethoscope. Subsequently the test

exercise session was started, which consisted of collective water

aerobics with a duration of 50 minutes, comprising five minutes

of preparatory activity, 20 minutes of aerobic exercises at 75%

of reserve HR (RHR), 20 minutes of strength exercises, and five

minutes of stretching. The HR was monitored by a heart rate

monitor (POLAR

RS800) during the entire session. After the

experimental session, ABPM was used to record BP during the

following 24-hour period.

For the LE-PEH, each individual remained at rest in a seated

position for 15 minutes, then the BP was measured three times

with a sphygmomanometer and stethoscope. Subsequently the

test exercise session was started, which consisted of aerobic

collective gymnastics with a duration of 50 minutes, including

five minutes of preparatory activity, 20 minutes of aerobic

exercises at 75% of RHR, 20 minutes of resistance exercises,

and five minutes of stretching. HR was monitored by a heart

rate monitor (POLAR

RS800). After the experimental session,

ABPM was used to record the BP during the following 24-hour

period.

Statistical analysis

The Shapiro–Wilk test was used to evaluate the normality of

the numerical data. Data are presented as mean

standard

deviation. An unpaired

-test with Welch’s correction was used

to compare the cardiopulmonary response between AE and LE,

as well as the magnitude of PEH at the second, 12th and 24th

hours after the session.

Two-way ANOVA was used to compare PEH for the sessions

by time (second, 12th and 24th hour), as well as determine

interaction effects (session and time), followed by Bonferroni’s

post hoc

test. A 5% significance level was set. All statistical

analyses utilised Graph Pad Prism 7.0

Results

Table 1 shows the characteristics of the experimental groups.

There were no differences between the groups by age, body mass

index, peak VO

, or resting systolic BP (SBP) and DBP.

Table 2 shows the HR and BP responses to maximal effort

recorded after the cardiopulmonary test. The values of HR and

Table 2. Cardiovascular response to maximal effort in

the cardiopulmonary test in hypertensive subjects

trained in aquatic and land exercise

AE (

10)

LE (

10)

HR (bpm)

134 (124.9–143.9)

147 (136.5–157.3)*

SBP (mmHg)

160 (150.9–191.7)

162.5 (151.3–177.9)

DBP (mmHg)

80.0 (72.4–89.6)

90.0 (84.1–90.5)*

AE: aquatic exercise; LE: land exercise; HR: heart rate; SBP: systolic blood

pressure; DBP: diastolic blood pressure. *

< 0.05 when compared to AE.

Mann–Whitney test, data expressed in median and 95% confidence interval.

Table 1. General profile of the two hypertensive groups

LE-PEH

10)

AE-PEH

10)

Age (years)

BMI (kg/m²)

26.4

3.4 25.7

2.8 27.3

3.3 26.5

5.2

Peak Vo

(ml/kg/min)

23.4

3.4 22.6

2.1 25.7

4.7 24.8

3.4

Resting SBP (mmHg)

140

4.4 153

5.0 130

8.3 128

9.8

Resting DBP (mmHg)

4.3 90

5.6 82

4.2 81

8.1

Antihypertensive drugs (

)

2 (1–2)

1 (1–2)

2 (2–3)

1 (1–2)

Diuretic (%)

ACE inhibitor (%)

ARB (%)

AE-PEH: aquatic exercise PEH; LE-PEH: land exercise PEH; AE: aquatic

exercise; LE: land exercise; PEH: post-exercise hypotension; VO

; volume of

oxygen; BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic

blood pressure; ACE inhibitor: angiotensin converting enzyme inhibitor; ARB:

angiotensin II receptor blocker. Data expressed as mean

SD.