Nutritional intake when cycling under racing and training conditions in professional male cyclists with type 1 diabetes

Figures & data

Table 1. Anthropometric, diabetes and maximum cardiopulmonary exercise test performance characteristics of study participants (n = 7).

Characteristic	Mean ± SD (Range)
Age (years)	28 ± 4 (23–35)
Diabetes duration (years)	10 ± 6 (1–18)
Height (m)	1.8 ± 0.1 (1.7–1.9)
Body mass (kg) (p = 0.47)	Training		Racing
	68.3 ± 5.6 (61.0–76.0)		67.7 ± 4.5 (62.8–75.4)
BMI (kg.m^−2) (p = 0.47)	Training		Racing
	21.4 ± 1.6 (19.0–23.0)		21.2 ± 1.2 (19.6–22.6)
HbA1c (%)	6.4 ± 0.4 (5.9–7.1)
HbA1c (mmol.mol^−1)	46 ± 4 (41.0–54.1)
HRmax (bpm)	187 ± 11 (173–202)
POmax (W)	409 ± 41 (340–460)
POmax (W.kg^−1)	6.0 ± 0.6 (5.2–6.7)
VO2max (L.min^−1)	5.0 ± 0.3 (4.7–5.4)
VO2max (mL.kg ^−1.min^−1)	73.9 ± 4.3 (68.6–79.2)
Basal insulin (Insulin Units) (p = 0.21)	Training	Racing
	14 ± 8 (4–25)	12 ± 7 (2–23)
Bolus insulin (Insulin Units) (p = 0.82)	Training	Racing
	12 ± 5 (5–18)	11 ± 6 (5–15)

Data are presented as mean ± SD (range). BMI: body mass index. HbA_1c: glycated haemoglobin. HRmax: maximum heart rate. Pmax: maximum power. VO_2max: Maximum volume of inhaled oxygen. P-values represent the degree of statistical difference in data between training and racing conditions.

Table 2. The performance variables of exercise under pre-season training and racing conditions.

Parameter	Training	Racing	P-value	Effect size
Duration (h)	4.5 ± 0.2 (0.7–6.3)	4.1 ± 0.2 (3.7–5.1)	0.120	0.68
Distance (km)	134 ± 10 (18–189)	164 ± 2 (144–175)	<0.001*	2.66
Speed (m.s^−1)	8.5 ± 0.2 (6.8–10.3)	10.7 ± 0.3 (9.4–11.7)	<0.001*	7.70
Cadence (rpm)	80 ± 3 (67–123)	76 ± 8 (60–84)	0.236	0.50
Power (W)	198 ± 24 (104–255)	207 ± 18 (139–266)	0.179	0.43
Power (W.kg^−1)	2.9 ± 0.2 (1.65–3.58)	3.1 ± 0.2 (2.2–3.7)	0.173	0.59
Power (%max)	49 ± 4 (27–64)	51 ± 2 (41–62)	0.186	0.56
HR (bpm)	132 ± 6 (93–163)	141 ± 4 (127–153)	0.011*	2.87
HR (%max)	71 ± 3 (52–80)	76 ± 8 (69–83)	0.016*	2.49

Data are average per ride, presented as mean ± SD (range). Power %_max derived from CPET power at VO_2max. HR: heart rate. * Denotes p ≤ 0.05.

Table 3. In-ride energy and macronutrient intake of professional road cyclists with type 1 diabetes under pre-season training and competitive road cycle racing conditions (n = 7).

Macronutrient	Training	Racing	P-value	Effect size
Energy (kJ)	3904 ± 519 (439–9138)	3954 ± 1360 (1477–7268)	0.909	0.04
Energy (kJ.h^−1)	849 ± 134 (188–1778)	933 ± 326 (364–1678)	0.419	0.33
Energy (kJ.kg^−1.h^−1)	11.97 ± 3.10 (0.00–25.02)	13.77 ± 4.60 (5.48–23.51)	0.426	0.44
Energy (kcal)	933 ± 124 (105–2184)	945 ± 325 (353–1737)	0.909	0.04
Energy (kcals.h^−1)	203 ± 32 (45–425)	223 ± 78 (87–401)	0.419	0.33
Energy (kcals.kg^−1.h^−1)	2.86 ± 0.74 (0.00–5.98)	3.29 ± 1.10 (1.31–5.62)	0.426	0.44
Carbohydrates (g)	192 ± 27 (21–451)	192 ± 64 (80–375)	0.991	0.00
Carbohydrates (% Energy)	82.7 ± 5.3	81.8 ± 4.4	0.662	0.17
Carbohydrates (g.h^−1)	41.9 ± 6.8 (10.4–90.4)	45.4 ± 15.5 (19.7–83.3)	0.548	0.24
Carbohydrates (g.kg^−1.h^−1)	0.6 ± 0.2 (0.00–1.32)	0.67 ± 0.22 (0.30–1.18)	0.537	0.36
Protein (g)	11.4 ± 2.1 (1.0–26.5)	7.8 ± 4.1 (0.0–21.0)	0.046*	0.95
Protein (% Energy)	4.9 ± 0.9	3.1 ± 1.0	0.014*	1.29
Protein (g.h^−1)	2.6 ± 0.6 (0.2–6.6)	1.9 ± 0.9 (0.2–4.6)	0.051	0.92
Protein (g.kg^−1.h^−1)	0.04 ± 0.01 (0.00–0.10)	0.03 ± 0.01 (0.00–0.07)	0.049*	0.77
Fat (g)	14.5 ± 6.0 (0.0–47.0)	15.4 ± 7.5 (2.0–37.0)	0.373	0.36
Fat (% Energy)	12.4 ± 5.4	15.0 ± 4.8	0.196	0.55
Fat (g.h^−1)	3.1 ± 1.3 (0.0–9.6)	3.6 ± 1.7 (0.4–8.5)	0.059	0.88
Fat (g.kg^−1.h^−1)	0.04 ± 0.02 (0.00–0.13)	0.05 ± 0.03 (0.01–0.12)	0.078	1.12

Data are average per ride, presented in absolute amounts, as a percentage contribution to the total in-ride energy yield (%), and relativised to both exercise duration in hours and body mass (kcals.kg⁻¹.h⁻¹ or g.kg⁻¹.h⁻¹).

Figure 1. Number of snacks consumed per ride and relative contribution of Fluid and Solid snacks. Percentage contributions of snack type usage between the two event types were statistically significant (p < 0.001). Data expressed as averages of riders in each event with SEM bars.

Table 4. Glycaemic responses to exercise under training and racing conditions.

Parameter	Training	Racing	P-value	Effect size
Mean iG (mg.dL^−1)	143.0 ± 42.2 (97.1–256.8)	158.3 ± 5.0 (115.5–222.4)	0.409	0.52
CoV iG (%)	17.8 ± 7.0 (7.6–40.0)	18.6 ± 2.9 (5.9–31.9)	0.787	1.19
TAR L2 (%)	6.3 ± 11.1 (0.0–72.7)	3.1 ± 3.5 (0.0–23.1)	0.441	0.67
TAR L1 (%)	15.5 ± 22.1 (0.0–94.1)	23.5 ± 4.2 (0.0–72.2)	0.495	0.55
TIR (%)	77.1 ± 32.8 (0.0–100.0)	73.4 ± 3.9 (7.7–100.0)	0.804	0.40
TBR L1 (%)	1.1 ± 1.5 (0.0–20.6)	0.0 ± 0.0 (0.0–0.0)	0.179	0.67
TBR L2 (%)	0.0 ± 0.0 (0.0–0.0)	0.0 ± 0.0 (0.0–0.0)	–	–

Data are reported as mean ± SD. iG: interstitial glucose. CoV: coefficient of variation. TBR L2: time below range level 2 (<54 mg.dL⁻¹[<3.0 mmol.L⁻¹]), TBR L1: time below range level 1 (54–69 mg.dL⁻¹[3.0–3.8 mmol.L⁻¹]), TIR: time in range (70–180 mg.dL⁻¹ [TIR; 3.9–10.0 mmol.L⁻¹]), TAR L1: time above range level 1 (181–250 mg.dL⁻¹[10.1–13.9 mmol.L⁻¹]) and TAR L2: time above range level 2 (>250 mg.dL⁻¹ [TAR 2; >13.9 mmol.L⁻¹]).