Dr Roger Ramsbottom

Department of Sport and Health SciencesOxford Brookes UniversityUnited Kingdom

11th Congress of Sport and Physical EducationPontevedra, Espaňa, 6-9 May, 2015.

THE UTILITY OF HEART RATE MEASURES IN SPORT AND EXERCISE SCIENCE

EXERCISE SCIENCE

ESTIMATION OF CARDIORESPIRATORY FITNESS FROM THE SUBMAXIMAL HEART RATE RESPONSE

ESTIMATION OF CARDIORESPIRATORY FITNESS FROM THE SUBMAXIMAL HEART RATE RESPONSE

Heart rate (b min-1)

Oxy

gen

upta

ke (L

min

-1) VO2max*

y = mx + cr = 0.998

*Aerobic fitness = maximal aerobic power (or VO2max)

VO2 Heart rate

1.10 109

1.35 123

1.55 140

2.20 156

ESTIMATION OF ENERGY EXPENDITURE FROM THE SUBMAXIMAL HEART RATE

Heart rate (b min-1)Oxy

gen

upta

ke (L

min

-1)

y = mx + cr = 0.998

*kJ 1.0 L O2 = 21 kJ energy

With an individual relationship between oxygen uptake and heart rate – the rate of energy expenditure can be estimated*.

MOUNT SNOWDON, WALES (1085-M) ESTIMATED ENERGY EXPENDITURE

Distance 25.51 kmMean HR 126 b min-1

EE 4,976 kcal (20.8 MJ)Duration 9 hrs 29 min

MOUNT SNOWDON, WALES (1085-M) HEART RATE RESPONSE AND WALK PROFILE

THE HEART: CARDIAC CONDUCTION SYSTEM

SA node ~ 60-100 bpm - sets the pace of the heartbeatAV node ~ 50 bpm - delays the transmission of action potentials

70-80/min

40-60/min

20-40/min

Intrinsic autorhymicity is influenced by parasympatheic and sympathetic neural input

PARASYMPATHETIC AND SYMPATHETIC INNERVATION OF THE HEART

PARASYMPATHETIC AND SYMPATHETIC INNERVATION OF THE HEART

HEART RATE VARIABILITY (HRV)

Different Heart Rate Variability (ms) in two individuals with similar Heart Rate (b min-1)

R-R Interval

TIME DOMAIN FREQUENCY DOMAIN ANALYSIS

SDNN:Standard deviation of the R-R interval in milliseconds.

Long-term control of HRV

RMSSD:Square root of the mean of the squares of successive R-R interval differences

Short-term control of HRV

High Frequency: Vagal activity

Low Frequency: Baroreceptor reflex

activity

Very Low Frequency: e.g. Renin-angiotensin

Autoregression analysis

POINCARÉ PLOTS

Quantitative measures:

SD1: Short-term HRV (SD of plot data along axis A)

SD2: Long-term HRV (SD of plot data along axis B) SD12 : (Poincaré dimension)Quantitative description of entire plot

A B

SD1 Measure of instantaneous beat-to-beat variability

SD2 Quantifies complex, long-term variability

STUDY I: SUBJECTS

Activity level

n Mean Supine Heart Rate

(b min-1)

Age (years)

Body Mass(kg)

Height (m)

Moderate 20 73(s=10)

26.1 (s=6.8)

67.5 (s=15.9)

1.66 (s=0.08)

High 20 59**(s=5)

23.8 (s=4.9)

63.4 (s=7.7)

1.66 (s=0.05)

**P<0.01Gilder and Ramsbottom (2008a) Measures of cardiac autonomic control in women with differing volumes of physical activity J. Sports Sciences, 26 (7): 781-786.

METHOD: MEASUREMENT OF HEART RATE VARIABILITY (HRV)

Polar S810i

Supine rest: 20

minutes of R-R

collection

Standing: 5 minutes of R-R collection

R-R data: HRV

Analysis

Time Domain:SDNN

RMSSD

Frequency Domain:(Autoregression analysis)

LF & HF LF/HF ratio (%)

Poincaré:SD1, SD2

RESULTS: HRV - MODERATE VERSUS HIGH PHYSICAL ACTIVITY GROUPS

Group

Moderate

High

RRI

827

1011**

SDNN

42.6

71.8**

RMSSD

42.1

82.2**

HF

230

515*

SD1

29.8

58.3*

SD1/SD2 ratio

0.39

0.49*

* P<0.05, **P<0.01

Each Poincaré plot shows 1000 R-R intervals

Participant A: Physical activity > 3 sessions per week, > 60 min; SD1 47.0 ms, SD2 87 ms, SD1/SD2 0.54

Participant B: Physical activity 1 session per week, > 30 min; SD1 11.9 ms, SD2 62.1 ms, SD1/SD2 0.19

POINCARÉ PLOTS: OVERTRAINING

Altered Poincaré plot shape in overtrained athletes (Mourot et al. 2004)

Trained Overtrained 1 Overtrained 2

R-R

Mourot et al. (2004) Decrease in heart rate variability with overtraining: assessment by the Poincaré plot analysis. Clin Physio Funct Imaging 24: 10-18

POINCARÉ PLOTS: CONGESTIVE HEART FAILURE

Plot shape indicates cardiac health status (Woo et al., 1994)

Normal Congestive Heart Failure

NA: 244 pg mL-1 NA: 750 pg mL-1Plasma NA:Normal range:150-300 pg mL-1

STUDY 2: HRV MAY INDICATE THE LACTATE AND VENTILATORY THRESHOLDSDi Michele et al. (2012) Estimation of the anaerobic threshold from the heart rate variability threshold in an incremental swimming test J. Strength & Cond. Res. 26 (11): 3059-3066.

James et al. (1989) Determination of anaerobic threshold by ventilatory frequency Int. J. Sports Med. 10 (3): 192-196.

Karapetian et al. (2008) Use of heart rate variability to estimate LT and VT Int. J. Sports Med. 29: 652-657.

Sales et al. (2011) Noninvasive method to estimate anaerobic threshold in individuals with type 2 diabetes Diabetology & Metabolic Syndrome 3: 1

HOW IS HRV DETERMINED?

Karapetian et al. (2008) Visual inspection …’point at which there was no further decline in HRV, thus indicating vagal withdrawal. Thus, this HRV deflection point was defined as the HRVT’.

Sales et al. (2011) ‘For the determination of the HRVT, a stabilization point lower than 3 milliseconds (ms) was adopted for the vagal activity indices (SD1 and RMSSD) plotted against the absolute workload’.

DATA FROM INCREMENTAL CYCLE ERGOMETRY

Work rate(W)

0306090

120150180210240

57.127.812.510.85.84.22.62.73.4

RMSSD(ms)

Blood lactate(mmol L-1)

VO2

(L min-1)VCO2

(L min-1)SD1(ms)

40.919.9

97.84.23

1.92

2.5

1.61.41.61.21.72.34.16.2

12.4

0.310.841.071.391.672.112.372.663.03

0.280.710.921.281.522.042.402.893.41

LACTATE THRESHOLD (0.4 MMOL L-1 ABOVE BASELINE)

0 50 100 150 200 250 3000.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

Work rate (w)

Blo

od L

acta

te C

once

ntra

tion

(mm

ol/L

)

Blood lactate(mmol L-1)

1.61.41.61.21.72.34.16.212.4

LT - 0.4 mmol L-1 sustained increase above baselineLT at 120 W

rest

move away from baseline lactate concentration >0.4 mmol L-1

VENTILATORY THRESHOLD VT1 (VCO2 PLOTTED AGAINST VO2)

0.50 1.00 1.50 2.00 2.50 3.00 3.500.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

f(x) = 1.50277442022907 x − 1.13296235684257R² = 0.998009535784683

f(x) = 0.992795801362949 x − 0.12393731882071R² = 0.99808678042964

VO2

(L min-1)VCO2

(L min-1)0.310.841.071.391.672.112.372.663.03

0.280.710.921.281.522.042.402.893.41

rest

VT1 breakpoint at 120 WVT1 at 120 W

HRV THRESHOLD (RMSSD VERSUS WORK RATE)

0 50 100 150 200 250 3000

5

10

15

20

25

30

RMSSD versus Work Rate

Work Rate (W)

RM

SS

D (m

s)

HRVT stabilization below 3 ms is at 2.6 msHRVT at 180 W

RMSSD(ms)

57.127.812.510.85.84.22.62.73.4

rest

HRV THRESHOLD (SD1 VERSUS WORK RATE)

0 50 100 150 200 250 3000

5

10

15

20

25

SD1 versus Work Rate

Work Rate (w)

SD

1 (m

s)

SD1(ms)

40.919.99.07.84.23.01.92.02.5

HRVT stabilization below 3 ms is at 1.9 msHRVT at 180 W

rest

VENTILATORY THRESHOLD VT2 RESPIRATORY COMPENSATION POINT (VE PLOTTED AGAINST VCO2)

0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.000

10

20

30

40

50

60

70

80

90

f(x) = 32.8274485770427 x − 29.2804788918188R² = 0.997483169096688

f(x) = 17.5117538864979 x + 6.4770276967594R² = 0.995630657102024

VCO2

V E

VT2 breakpoint at 180 WVT2 at 180 W

VCO2

(L min-1)0.280.710.921.281.522.042.402.893.41

9.618.722.829.632.342.350.064.783.3

VE

(L min-1)Work rate

(W)0

306090

120150180210240

SUMMARYHEART RATE MEASURES CAN:

Estimate energy expenditure (kJ) during steady-rate submaximal exercise.

Estimate cardiorespiratory fitness (VO2max) based on the submaximal heart rate response.

Indicate the training status of an athlete.

Indicate cardiac autonomic health status in clinical populations.

May reflect the lactate and ventilatory thresholds during incremental exercise.