Optimal strength of erection is necessary for penetration and successful intercourse. Failure of penetration due to lack of penile strength is considered as Erectile Dysfunction or impotence.
If a man is unable to get an erection, it could be due to physical and life style factors (such as high cholesterol, diabetes, high blood pressure or heavy smoking) or psychological factors due to stress, interpersonal/intimacy issues with partner, performance anxiety in man or female dysfunction such as vaginismus.
Getting softer soon after achieving an erection is inability to sustain an erection; this condition could be due to difficulty in maintain arousal state or swift return of the engorging blood from penis back to the body.
Healthy men with positive attitudes towards sexuality are known to enjoy sexual health to the ripe old age. However, diseases, physical disability, hormonal changes as one ages and ageing itself can compromise erectile function.
For men who are suffering from Erectile Dysfunction, the best solution is to seek a professional consultation who can advise on the use of well-established medications like viagra, cialis or levitra.