"Stress is what arises when something you care about is at stake." Although she calls it a "conception" rather than a "definition", effectively this becomes her working definition of stress, and it is problematic. As a conception or a definition, it is so broad as to be almost meaningless, covering as it does every conceivable situation which solicits some kind of response, from a making a routine effort, through small demands, bigger challenges, adversity, to major threats and mortal danger. If something dear to me were not at stake, I wouldn't get out of bed in the morning. I do not call that a stress, although some people in some circumstances would. In a sense, McGonigal is telling us to mentally shift more of our life from the "threat" side of the continuum to the "challenge" side. That is a commonly used strategy already in stress management.
But the point is, the definition covers most of what most of us do every day: living our lives. In that context, it is relatively uncontroversial to assert that a positive mindset is likely to have positive effects. On the other hand, the popular conception of stress is a distressing feeling of being under pressure. One could assert, and I do, that this idea constitutes a sort of folk definition, and it defines stress as a distressing experience. Lazarus' (1966) explanation of stress is more in line with the this folk definition: "Stress arises when individuals perceive that they cannot adequately cope with the demands being made on them or with threats to their well-being."
While there may be opportunities to be derived from any adversity, clearly if we change our definition to have it include the the whole range of human experiences involved in living, we are dealing with a very different kettle of fish, in which all the upsides are much more easily appreciable. McGonigal has exploited a semantic paradox. But, paradox resolved, I am not sure that there is a great deal there that is new.
There is a problem also with McGonigal's assumptions about how people view the relationship of stress and stressor, which is rather ambiguous and fluid. A stressor is an event or situation which triggers stress. Stress is the process within the person by which a stressor results in certain kinds of physiological, cognitive, emotional and behavioural responses. The range of responses considered "stress responses" is wide, and again, subject to the limits imposed by our definitions. McGonigal herself sometimes appears to use the words stress and stressor interchangeably, which does not help to make her case. Stress is a difficult concept in the abstract. We associate it with the contexts which trigger it or with the feelings triggered by it. The lay public does not generally use the word "stressor": most people use "stress" to mean both the perceived outward source of their stress, and the feelings triggered by that outward source. Now, when we suggest to a person that they begin view stress positively, it is most likely that they will be conceptualising their stress not as stress itself, but as the stressors that trigger it or the feelings it produces. Does it matter? In practice, probably not, but it may weaken McGonigal's claim that this is a new science of stress. Engendering a positive view of challenges is standard in cognitive approaches to stress.
Thirdly, it is basic science that a correlation does not imply causation. Correlations may be legitimately presented along with other kinds of evidence to imply causation, and this McGonigal does. Yet one has the impression that she relies a little too heavily on the former. Further, on occasion she ignores the aforementioned principle of logic, in order to present a correlation as implication of causation with little supporting evidence.
This book claims to present a "new science of stress", and to be fair a lot of the science cited is recent. Yet I'm not convinced that many of the ideas are actually new. For example, we are told that stress responses other than "flight and flight" have been largely ignored by psychologists, and we are introduced to two other, more sophisticated ones: "challenge" and "tend and befriend". But it is a false argument. It is already widely recognised that there are many ways of responding to stress within the human range. Problems occur (i.e. we stress) when we inappropriately rely on our primitive responses.
It is unclear to me exactly how great the effect of stress mindset is. According to McGonigal it is surprisingly large, consistent and long-lasting. Yet in one of their studies Crum and Salovey (2013) - one group of workers whom McGonigal cites extensively - found that compared to traditional "stress influencing variables" (amount of stress, appraisal, coping strategies) stress mindset accounted for only an additional 2 to 3% of the variance in measures of health and life satisfaction, and did not account for any significant additional variance in work performance.
In summary, McGonigal's manoeuvre is to bend our definition of stress into one which we can regard positively, and then suggest that we do so. But most of us cannot regard stress in the abstract, we regard it in terms of the context that triggers it or the feelings it engenders. Viewing these things positively is not a new proposal. The relative size of effect of the stress mindset is unclear, and in one study has been shown to be small.
However, for me there are two important take-homes from McGonigal's book. Firstly, it may be counter-productive for me as a health care practitioner to emphasise to my patients the negative effects of stress. This may provoke anxiety that in turn can feed stress. I know that this is a valuable observation that I have probably underestimated in the past. Secondly, that single, simple mindset interventions can help people avoid the negative effects of stress and indeed, thrive in the face of adversity. I had not previously considered that a single intervention might produce long-lasting effects. Although academically weightier and more substantial than popular self-help guides, The Upside of Stress will be valuable to the stressed lay person as well as to workers at the coalface.
McGonigal K. The Upside of Stress: Why Stress Is Good for You and How to Get Good at It 2015, Avery.
Crum A. J. & Salovey P. Rethinking Stress: The Role of Mindsets in Determining the Stress Response J Pers Soc Psychol. 2013 , Apr; 104(4), 716-33.
Lazarus, R.S. Psychological stress and the coping process. 1966, McGraw-Hill.