Glycogen কী?

Example 7.9 (The marathon wall)

Running consumes about $4\,\mathrm{kJ}$ per kilogram of body mass per kilometre; a $70\,\mathrm{kg}$ runner spends $280\,\mathrm{kJ}/\mathrm{km}$, and a marathon costs $11\,800\,\mathrm{kJ}$. The glycogen stores hold about $8500\,\mathrm{kJ}$. If the runner burns glycogen too fast, the stores run out around the thirtieth kilometre; the muscles must then rely on fat, which supplies energy at barely half the rate, and the pace collapses — "hitting the wall". Trained runners burn a larger share of fat from the start, and eat carbohydrate during the race.

Example 7.11 (An hour of cycling)

One hour at $150\,\mathrm{W}$ on the pedals: metabolic power about $600\,\mathrm{W}$, energy $600 \times 3600 = 2.16 \times 10^{6}\,\mathrm{J} \approx 2200\,\mathrm{kJ}$; oxygen $2200/20 = 110\,\mathrm{L}$, i.e. $1.8\,\mathrm{L}/\mathrm{min}$ — consistent with the curve. If half comes from carbohydrate: $1100/17 \approx 65\,\mathrm{g}$ of glucose or glycogen, and $1100/38 \approx 29\,\mathrm{g}$ of fat.