Lowering & raising G tolerance
G tolerance varies with the individual. It depends on (TC AIM AIR 3.15.2): peak value, duration of the force, rate of onset.
| Lowers | Raises | |
|---|---|---|
| Body state | Obesity, ill health, low blood pressure, many medications | Good physical conditioning, diet |
| Day to day | Fatigue, smoking, hypoxia, hangovers | Adequate hydration |
| Blood sugar | Hypoglycaemia (low) markedly lowers | Normal blood sugar |
Dealing with G (TC AIM AIR 3.15.3, 3.15.4):
| Technique | Effect |
|---|---|
| Valsalva manoeuvre: bear down against closed glottis, nose and mouth closed | About +2G; temporary, hard to maintain; original anti-G straining manoeuvre |
| Tense calf and thigh muscles | Less blood pooling |
| Squat in seat or lean slightly forward, tensing abdominal muscles | Shorter heart-to-brain distance, higher blood pressure |
Training:
| Training | Effect on G tolerance |
|---|---|
| Weight lifting | Builds, better than intensive aerobic |
| Moderate aerobic (20-30 min daily) | Helps |
| Runs under 5 km | Helps |
| Long-distance running | Decreases: slows resting heart rate, raises G-LOC risk |
Trap: treating G tolerance as fixed; long-distance running lowers it.
References
- TC AIM AIR 3.15