Diabetes Hands Foundation presented a poster abstract at the AADE in Philadelphia that uses the data collected during the 2012 Big Blue Test. Our Big Blue Test scientific poster was awarded a big blue 1st place ribbon for “Immediate Impact of Exercise on Blood Glucose in People with Diabetes.”

1. Varying Durations and Intensities of Exercise and Blood Glucose
Responses
S.R. Colberg (Human Movement Sciences Dept., Old Dominion University), M.J. Hernandez (Diabetes Hands Foundation), F. Shahzad
abstract
During the 2012 Big Blue Test (run by the Diabetes Hands
Foundation to raise awareness of the impact of exercise on
diabetes control), participants anonymously entered their diabetes
status, type of exercise done, intensity (moderate or vigorous),
duration (10 or less, 11 to 19, 20 to 29, or 30 or more min), time
elapsed since most recent meal, and blood glucose (BG) readings
before and after the activity at www.bigbluetest.org. A total of 7,157
exercise-associated BG pairs (before/after) from persons with
diabetes were included. Walking was the most frequent activity
(48.5%), followed by other (non-specified) exercise (18.7%),
running/jogging (11.9%), cycling (8.8%), conditioning machines
(6.4%), and dancing (5.7%). Overall, mean BG levels were 31.3
mg/dl lower (±47.1) following any exercise, a decrease of 16.8%.
Longer exercise times generally resulted in increasingly greater
decreases in BG for moderate exercise (p<0.001), although results
were mixed for vigorous (table). The largest decrease in BG
occurred following 30 or more min of exercise undertaken 1 hr
(-49.3±53.1 mg/dl) or 2 hr (-46.4±49.8) after the last meal
(p<0.001). Overall, 75.8% of participants experienced a decrease in
BG, 8.8% were unchanged (±5 mg/dl), and 15.4% had an increase.
Thus, this year’s Big Blue Test confirms that participation in varying
types, intensities, and durations of exercise generally lowers BG in
most individuals, although exercise of longer duration is likely most
effective.
introduction
For most people with any type of diabetes, engaging in
physical activity has a blood glucose lowering effect and
can assist in diabetes management.1 The Big Blue Test
(BBT) is an online initiative run by the Diabetes Hands
Foundation to raise awareness of the importance of
physical activity in managing diabetes by asking diabetic
individuals to participate in an activity and record their
blood glucose levels pre- and post-exercise. In 2012, the
third such initiative was undertaken.
The purpose of the 2012 BBT was to collect specific data
not just on the impact of exercise type on blood glucose
levels, but also intensity and duration, in response to a
single bout of activity. In addition, the glycemic impact of
exercise timing with regard to intake of an individual’s last
meal was also examined in both insulin and non-insulin
users with diabetes.
methods
results
• During the 2012 BBT, data were collected online through
BigBlueTest.org or via the BBT iPhone app. Participants
anonymously entered their diabetes status, type of exercise
done, intensity, duration, time elapsed since most recent
meal, and blood glucose readings before and after their
physical activity. Participants were free to enter results from
more than one bout of exercise, but data from each session
were entered as a separate result.
• Based on the frequency of exercise type responses given in
the 2011 BBT, this year’s choices were limited to the
following options: walking, running/jogging, cycling,
conditioning machines, dancing, and other (non-specified).
• Exercise intensity was reported as either moderate or
vigorous. Exercise duration choices were as follows: 10
minutes or less, 11 to 19, 20 to 29, or 30 or more minutes.
• Participants reported the timing of exercise following the last
meal as one of the following: 30 minutes ago, 1 hour ago, 2
hours ago, or 3 (or more) hours ago.
• Data were reported as mean ±SD and analyzed using
ANOVA, with groups varying by analysis based on the
factors considered. Significance was set at p<0.05.
• A total of 7,157 exercise-associated blood glucose pairs
(before/after exercise) from individuals with any type of
diabetes were included (Table 1).
• Walking was the most frequent activity (48.5%), followed by
other exercise (18.7%), running/jogging (11.9%), cycling
(8.8%), conditioning machines (6.4%), and dancing (5.7%).
• Overall, walking resulted in the smallest decrease in blood
glucose levels (-25.0 ±42.4 mg/dl) compared to other
exercise (-33.5 ±50.0), running/jogging (-40.1 ±55.1),
cycling (-42.4 ±48.8), conditioning machines (-35.9 ±48.8),
and dancing (-37.4 ±45.3; p<0.05).
• Mean blood glucose levels were lower (-31.3 ±47.1 mg/dl,
or 16.8%) following all exercise (types, durations, and
intensities). Moderate exercise resulted in a mean decrease
of -32.7 ±44.1 mg/dl, whereas vigorous activity blood
glucose decreased by -28.0 ±53.6 (p<0.05).
• When considered by time after last meal and exercise
duration for moderate activity only, longer durations
resulted in lower blood glucose levels for all meal timings
except for 3 or more hours afterwards (Table 2).
• With all exercise included, longer exercise times resulted in
increasingly greater decreases in blood glucose levels
(p<0.05); results were similar after moderate exercise
(p<0.001), although somewhat mixed for vigorous (Table 1).
Table 1. MEAN CHANGE IN BLOOD GLUCOSE (mg/dl) BY EXERCISE
INTENSITY AND DURATION
11 to 19 min
20 to 29 min
30 min or more
• With all glucose pairs included in analyses, exercise
undertaken 1 or 2 hours after the last meal led to a similar
decrease in blood glucose (-40.1 ±47.2 and -40.1 ±45.9
mg/dl, respectively), but both were significantly more than
exercise done either 30 minutes (-28.6 ±50.6) or 3 hours
or more (-21.2 ±44.0) afterwards (p<0.05).
• The largest decrease in blood glucose levels occurred
following a duration of 30 or more minutes of either
intensity of exercise undertaken 1 hour (-49.3 ±53.1
mg/dl) or 2 hours (-46.4 ±49.8) after the last meal
(p<0.001), compared to 30 minutes (-34.3 ±53.5) or 3
hours or more (-19.6 ±47.0) afterwards.
Table 2. MEAN CHANGE IN BLOOD GLUCOSE (mg/dl) BY TIMING OF
LAST MEAL AND DURATION OF MODERATE EXERCISE
results
10 min or less
results
10 min or less
30 min
ago
-18.7 (48.4)∞†‡
11 to 19 min
20 to 29 min
30 min or more
-21.4 (39.7)∞†‡ -20.6 (46.4)∞†‡¥ -33.5 (49.8)*∞†
All
Exercise
n=7,157
-17.9 (44.9)◦
-25.0 (34.4)◦
-30.9 (42.0)◦
-34.5 (51.7)◦
1 hr ago
-7.1 (45.9)∞†
-29.9 (31.5)*∞† -31.7 (35.4)*∞†
-47.2 (50.1)*
Moderate
n=5,051
-16.9 (43.8)
-25.6 (32.9)
-29.9 (40.2)*
-39.0 (48.6)*∞†
2 hrs ago
-22.3 (41.3)∞†
-28.1 (31.5)*∞†
-45.8 (46.8)*
3 (or
more) hrs
ago
• Overall, 75.8% of participants experienced a decrease in
blood glucose following exercise, 8.8% had unchanged
levels (i.e., within 5 mg/dl), and 15.4% had an increase for
all exercise (type, intensity, and duration) combined.
conclusion
The 2012 Big Blue Test confirms that participation in varying
types, intensities, and durations of exercise generally lowers
blood glucose levels in most individuals with diabetes,
although exercise of longer duration (regardless of the
intensity) is likely most effective in lowering them.
The timing of exercise following the last meal also needs to
be considered when anyone with diabetes undertakes any
physical activity since elapsed time since eating may impact
the usual glycemic responses to exercise.
-17.1 (39.1)∞†‡ -21.5 (30.9)∞†‡¥ -27.7 (37.9)*∞† -29.4 (45.9)*∞†
Vigorous
n=2,106
-25.1 (51.4)
-22.1 (40.8)‡
-36.1 (49.9)*∞¥
-27.6 (55.5)*‡
◦For all exercise, all values differ from each other (p<0.05); for moderate and vigorous,
*p<0.001 vs. 10 min or less mod, ∞p<0.001 vs. 11 to 19 min mod, †p<0.001 vs. 20 to
29 min mod; ‡p<0.001 vs. 30 min or more mod; ¥p<0.001 vs. 11 to 19 min vigorous.
-37.2 (41.4)*
*p<0.05 vs. 1 hr ago, 10 min or less, ∞p<0.001 vs. 1 hr ago, 30 or more min, †p<0.05
vs. 2 hrs ago, 30 or more min; ‡p<0.05 vs. 2 hrs ago, 20 to 29 min; ¥p<0.05 vs. 30 min
ago, 30 min or more; all values are mean (SD).
references
Colberg SR, Sigal RJ, Fernhall B, Regensteiner JG, Blissmer BJ, Rubin RR,
Chasan-Taber L, Albright AL, Braun B; American College of Sports Medicine;
American Diabetes Association. Exercise and type 2 diabetes: the American College
of Sports Medicine and the American Diabetes Association: joint position statement.
Diabetes Care. 2010;33(12):e147-67.
1
www.bigbluetest.org