The effect of ageing on ATP generation

Two mechanisms for loss of mitochondrial function have been suggested (i) damage caused by the chronic production of free radicals within the mitochondria and (ii) somatic mutations in the mitochondrial genome, which progressively accumulate during a lifetime. 

Loss of mitochondria will not only decrease the maximal exercise performance but, for any given level of exercise, aerobic generation of ATP will be insufficient, so that a greater proportion must be generated from anaerobic metabolism, i.e. glycogen conversion to lactic acid, so that muscle glycogen and pH are decreased which can result in fatigue (discussed in Chapter 13). 

Ageing is an increasing problem in developed countries. For example, by 2020, there will be 10 million North Americans aged 85 or more. This has enormous implica- 

Overview of ATP generation from food to essential life processes 

There are at least three ways in which mitochondrial ATP generation can be impaired mutations in mitochondrial DNA, mutations in nuclear DNA and effects of toxic compounds. The reactions in mitochondrial metabolism that are affected by some toxic compounds are described in Appendix 9.12. 

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