FIGURES
Studies identified
(n=48)
Abstract not available (n=1)
Abstracts assessable
(n=47)
Excluded after screening abstract
(n=31):
- Did not suffice domain, determinant
or outcome (n=16)
- No original data (n=9)
- Language barrier (n=4)
- Case report (n=2)
Complete article not available (n=5)
Judged articles
(n=11)
Excluded after assessment of full text
article (n=4):
- Outcome not compatable (n=4)
Studies included in
analysis (n=7)
Figure 1 Flowchart. Selection of articles based on the association between sports
(type and intensity) and gastro-esophageal reflux in the literature study.
Figure 2
A) Average percentage of time with pH<4 during exercise ± standard deviation
of two included studies. The dotted line indicates the maximum percentage of
time with pH<4 in healthy individuals.9, 12
B) Average percentage of time with pH<4 related to the intensity of exercise as a
percentage of VO2 max ± standard deviation.11, 13, 14
Figure 3
The prevalence of reflux symptoms in daily life, during and immediately after rowing,
during the most vigorous rowing period in 103 included rowers, designating the
presence of reflux symptoms in this particular period; * p<0.05, ** p<0.01.
TABLES
Study
Method
Study population
Exercise
Method of reporting
reflux
% time
Symptoms
pH ≤4
N
Trained
Mean ageyears
(SD/ range)
Gendermale
N (%)
Type
N
Intensity
Rest
60% VO2max
75% VO2max
90% VO2max
Rest
40% VO2max
60% VO2max
75% VO2max
90% VO2max
Rest
70% VO2max
Yes
Yes
Yes
Yes
No
Yes
Soffer
1993
pH monitoring
8
Yes
25 (20-32)
8 (100)
Cycling
8
Soffer
1994
pH monitoring
9
No
25 (20-43)*
4 (44)
Cycling
9
Yazaki
1996
pH monitoring
10
Yes
20-44
8 (80)
Rowing
10
Peters
2000
pH monitoring
7
Yes
27 ± 2
7 (100)
Cycling
Running ‡
7
Rest
70% VO2max
Yes
Yes
Choi
2003
pH monitoring
12
No
27 ± 5
12 (100)
Running
12
Yes
Yes
Collings
2003
pH monitoring
30
Yes
27 (90)
363
Yes
10
10
10
178
Yes
Questionnaire
Cycling
Running
Weightlifting
Surfing•
Yes
Norisue
2009
29 ± 5
34 ± 12
30 ± 7**
33 ±12
31 ±10†
Rest
Walking
40% MHR
70% MHR
Rest
65% MHR
85% MHR
Short-boarders
Long-boarders
No
Yes
Other types of exercise••
185
232 (63)
Table 1:
Descriptive data from the included articles from the literature search. MHR=maximum heart rate, N=number, SD=standard deviation,
VO2max=maximal oxygen uptake, *median, **average age of cyclists, runners and weightlifters, †average age of surfers and other athletes,
‡enrolled triathlon athletes, •sports other than surfing, ••long surf boards (> 2.44 m) vs. short surf boards (<2.44 m).
Total
N=196 (%)
General
Gender: male
Higher education level
Age- mean (SD)
BMI- median (IQR)
Ever smoked- yes
Packyears- median (IQR)
Rowing
Type of
•
•
•
•
rower
Aspirant or recreation
Tour
Marathon
Competition
Number of rowing years- median (IQR)
Number of rowing hours per week, most vigorous
period- median (IQR)
99 (51)
164 (84)
59 (14)
23 (22-25)
58 (30)
6 (2-12)
55
41
12
88
(28)
(21)
(6)
(45)
14 (7-25)
6 (4-10)
Table 2. Characteristics of the 196 included rowers participating in the questionnaire survey.
BMI=body mass index, IQR=interquartile range, N=number, SD=standard deviation.
Reflux
symptoms
N (%)
28 (27)
No reflux
symptoms
N (%)
75 (73)
p-value
Gender
 Male (n=54)
 Female (n=49)
10
18
(36)
(64)
44
31
(59)
(41)
0.047
Age- mean (SD)
52
(31-60)
45
(21-60)
0.24
BMI- median (IQR)
23
(21-24)
22
(21-24)
0.48
Type of rower
 Aspirant or recreation (n=26)
 Tour (n=15)
 Marathon (n=9)
 Competition (n=53)
6
6
6
10
(21)
(21)
(21)
(37)
20
9
3
43
(27)
(12)
(4)
(57)
0.02
(4-10)
0.65
Rowing hours per week- median (IQR)
6
(3-10)
6
Table 3. Reflux symptoms during the most vigorous rowing period. A total of 103 rowers that
designated the occurrence of reflux symptoms in this particular period were included in the
analysis. BMI=body mass index, IQR=interquartile range, N=number, SD=standard
deviation.