Does smoking tobacco increase work capacity?

Question

A colleague stated that he heard of studies stating that nicotine is an upper and would increase work effort. A short Google search showed many sources showing many strongly positive effects of smoking, although not necessarily of nicotine.

For example, this source is titled "Science is conclusive: Tobacco increases work capacity", using among other sources this meta-study.

Although the negative effects of smoking are undeniable, I had not expected to see so many positive ones. Are these studies all heavily funded by the tobacco-industry, or is there no reason to suspect foul play?

Answer 1

Issue: Whether smoking tobacco increases work capacity?

Evidence:

1. The meta analytic study quoted in the OP's source is only directly about the effects of nicotine on cognition and is not connected with the other chemicals emitted during tobacco smoking i.e. cigarette smoke contains 4000-7000 chemicals out of which 70 is carcinogenic. So this cannot be taken as direct support for correlating smoking and work capacity.

In a recent meta-analysis of over 40 studies, including non-smokers and minimally deprived or non-deprived smokers, Heishman et al. (2010) divided studies into reaction time (RT) or accuracy-based outcomes and found beneficial nicotinic modulation of simple motor performance, alerting attention (accuracy and RT) and orienting attention (only RT, not accuracy). Furthermore, their results also reintroduced the possibility of a nicotinic involvement in memory, considering that both short-term episodic memory accuracy and working memory RT generally improved with nicotine.

2. Research shows that there are significant effects shown by nicotine administration on pre-attentional processing, attention and distraction. However, those effects are noted to be prompt but inefficient.

The majority of early human studies showing a beneficial effect of nicotine on attention employed nicotinic manipulations in smokers. Both an acute dose of nicotine in non-smokers and chronic nicotine use in temporarily abstaining smokers diminishes perceptual thresholds while simultaneously slowing perceptual speed. In addition, both acute and chronic nicotine use reduce attentional selectivity but leaves short-term memory capacity unimpaired. Crucially, the nicotine-induced slowing in perceptual processes stands in contrast to prior reports of nicotine-induced speeding of motor processes.

3. Nicotine's neuroprotective effects are studied for treatment of Parkinson's disease.

4. There is also significant risk associated with smoking of tobacco such as blood vessel narrowing and blood pressure changes which depends on the type of smoking and its duration.

Fowles and Dybing (2003) suggested an approach to identify the chemical components in tobacco smoke with the greatest potential for toxic effects. They considered the risk for cancer, cardiovascular disease, and heart disease. Using this approach, these investigators found that 1,3-butadiene presented by far the most significant cancer risk; acrolein and acetaldehyde had the greatest potential to be respiratory irritants; and cyanide, arsenic, and the cresols were the primary sources of cardiovascular risk. Other chemical classes of concern include other metals, N-nitrosamines, and polycyclic aromatic hydrocarbons (PAHs).

5. The medium used for consumption of nicotine such as cigarettes, cigars, pipes, gums, patches and vapourizers have been found to have a sudden effect on the addictive potential.

For example, the extent of liking, and therefore the addiction potential for these products, are related to the speed of nicotine delivery (Henningfield and Keenan 1993). Nicotine delivered through cigarette smoking and intravenously shows the greatest dose-related liking for the drug, and nicotine delivered transdermally is associated with the least liking (Henningfield and Keenan 1993; Stratton et al. 2001).

Meaning:

1. Consumption of tobacco or smoking of cigarettes as a aid for nicotine intake is still harmful either in work, play or life due to its addictive and abusive potential and also because of the relation between cancer and chemical ingredients present in combination with tobacco which is demonstrated in several research studies.

Consumption of tobacco has been shown in numerous studies to be harmful, and nicotine does pose potential harm if abused.

2. Nicotine shows potential cognitive effects which may play a role in affecting working memory.

“We’ve demonstrated that you can get an effect from nicotine on prospective memory,” Rusted said. “It’s a small effect, maybe a 15 percent improvement. It’s not something that’s going to have a massive impact in a healthy young individual. But we think it’s doing it by allowing you to redeploy your attention more rapidly, switching from an ongoing task to the target. It’s a matter of cognitive control, shutting out irrelevant stimuli and improving your attention on what’s relevant.”

3. Currently there is insufficient evidence for calculating an optimal dose of nicotine to obtain cognitive benefits in nonsmokers.